Retirement and Postemployment Benefits (Plan Assets and Expected Cash Flows) (Details) - USD ($) $ in Millions	1 Months Ended		12 Months Ended
	Jan. 31, 2021	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Pension Plan [Member] | U.S. [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	$ 4,068	$ 4,068	$ 4,068	$ 3,109	$ 4,068	$ 3,585
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	4,068		3,585	3,109
Balance at end of period		4,068	4,068	3,585
Defined Benefit Plan Estimated Future Employer Contributions (Numeric) [Abstract]
Employer contributions			$ 115	63
Amount to be contributed to plan in the next fiscal year					0
Expected amount of benefit payments in the next period for non-qualified plans					18
Estimated Future Benefit Payments (Details) [Abstract]
2021					296
2022					284
2023					279
2024					275
2025					273
2026-2030					$ 1,273
Pension Plan [Member] | U.S. [Member] | Subsequent Event [Member]
Defined Benefit Plan Estimated Future Employer Contributions (Numeric) [Abstract]
Employer contributions	30
Pension Plan [Member] | U.S. [Member] | Master Trust [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					100.00%	100.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					100.00%
Assumptions Used in Calculations (Numeric) [Abstract]
The limited lives of four partnership of private equity investments (in years)			10 years
The amount of potential liability that maybe required to be funded by the master trust during life of the partnership					$ 45
Number Of Days Notice Required To Redeem Shares			45 days
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	4,068	4,068	$ 3,585	3,585	4,068	$ 3,585
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	4,068		3,585
Balance at end of period		4,068	4,068	3,585
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	695	695	685	685	695	685
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	695		685
Balance at end of period		695	695	685
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	1,007	1,007	949	949	1,007	949
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	1,007		949
Balance at end of period		1,007	1,007	949
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	15	15	24	46	15	24
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	15		24	46
Actual return on plan assets relating to assets still held at the reporting date				3
Actual return on plan assets relating to assets sold during the period				3
Purchases, sales and settlements			(9)	(28)
Balance at end of period		15	15	24
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Cash And Cash Equivalents [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					300	182
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Cash And Cash Equivalents [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					300	182
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Cash And Cash Equivalents [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Cash And Cash Equivalents [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Equity Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					742	451
Measured at fair value not using net asset value per share					60	194
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Equity Securities [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					60	194
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Equity Securities [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Equity Securities [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | International Equity Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					566	554
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Commingled Debt Equity Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					712	621
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | US Treasury And US Government Sponsored Agency Debt Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					336	310
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | US Treasury And US Government Sponsored Agency Debt Securities [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					335	309
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | US Treasury And US Government Sponsored Agency Debt Securities [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					1	1
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | US Treasury And US Government Sponsored Agency Debt Securities [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Corporate Debt Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					1,045	951
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Corporate Debt Securities [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Corporate Debt Securities [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					1,030	931
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Corporate Debt Securities [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					15	20
Fair value at end of period	15	15	20	20	15	20
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	15		20	25
Actual return on plan assets relating to assets still held at the reporting date				(1)
Actual return on plan assets relating to assets sold during the period				3
Purchases, sales and settlements			(5)	(7)
Balance at end of period		15	15	20
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Other Debt Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					13	14
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Other Debt Securities [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Other Debt Securities [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					13	14
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Other Debt Securities [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Real Estate Alternative Investments [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					76	88
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Total Trust Assets Prior to Adjustments [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	4,110	4,110	3,628	3,628	4,110	3,628
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	4,110		3,628
Balance at end of period		4,110	4,110	3,628
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Private Equity Alternative Investments [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					68	62
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Hedge Fund Of Funds Alternative Investments [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					223	194
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Derivatives [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					(37)	3
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Derivatives [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Derivatives [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					(37)	3
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Derivatives [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Insurance Contracts [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	4
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Insurance Contracts [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Insurance Contracts [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Insurance Contracts [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	4
Fair value at end of period	0	0	0	21	0	4
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	0		4	21
Actual return on plan assets relating to assets still held at the reporting date				4
Actual return on plan assets relating to assets sold during the period				0
Purchases, sales and settlements			(4)	(21)
Balance at end of period		0	0	4
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Receivables And Payables Net [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	116	116	99	99	116	99
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	116		99
Balance at end of period		116	116	99
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Account 401 H [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	(158)	(158)	(142)	(142)	(158)	(142)
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	(158)		(142)
Balance at end of period		(158)	(158)	(142)
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Limited Partner
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					$ 6	$ 0
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Growth Portfolio [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					56.00%	57.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					55.00%
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Growth Portfolio [Member] | Equity Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					34.00%	34.00%
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Growth Portfolio [Member] | Debt Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					13.00%	14.00%
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Growth Portfolio [Member] | Alternative Investments [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					9.00%	9.00%
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Immunizing Portfolio [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					43.00%	42.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					43.00%
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Immunizing Portfolio [Member] | Debt Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					33.00%	35.00%
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Immunizing Portfolio [Member] | Derivatives [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					10.00%	7.00%
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Liquidity Portfolio [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					1.00%	1.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					2.00%
Pension Plan [Member] | U.K. [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					100.00%	100.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					100.00%
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	9,970	9,970	9,970	7,801	$ 9,970	$ 8,945
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	9,970		8,945	7,801
Balance at end of period		9,970	9,970	8,945
Defined Benefit Plan Estimated Future Employer Contributions (Numeric) [Abstract]
Employer contributions			$ 272	278
Amount to be contributed to plan in the next fiscal year					183
Recurrence of formal actuarial valuations (in years)			3 years
Percentage of deficit funding requirements permitted to recover in rates			78.00%
Estimated Future Benefit Payments (Details) [Abstract]
2021					362
2022					367
2023					370
2024					375
2025					377
2026-2030					1,884
Pension Plan [Member] | U.K. [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	412	412	$ 154	154	412	154
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	412		154
Balance at end of period		412	412	154
Pension Plan [Member] | U.K. [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	4,209	4,209	3,824	3,824	4,209	3,824
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	4,209		3,824
Balance at end of period		4,209	4,209	3,824
Pension Plan [Member] | U.K. [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	0	0	0	0	$ 0	$ 0
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	0		0
Balance at end of period		0	0	0
Pension Plan [Member] | U.K. [Member] | Cash And Cash Equivalents [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					4.00%	2.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					0.00%
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					$ 412	$ 154
Pension Plan [Member] | U.K. [Member] | Cash And Cash Equivalents [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					412	154
Pension Plan [Member] | U.K. [Member] | Cash And Cash Equivalents [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Pension Plan [Member] | U.K. [Member] | Cash And Cash Equivalents [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					$ 0	$ 0
Pension Plan [Member] | U.K. [Member] | U.K. Companies Equity Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					0.00%	0.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					2.00%
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					$ 1	$ 22
Pension Plan [Member] | U.K. [Member] | European Companies Excluding U.K. Equity Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					0.00%	0.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					1.00%
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					$ 3	$ 54
Pension Plan [Member] | U.K. [Member] | Asian Pacific Companies Equity Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					0.00%	0.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					1.00%
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					$ 3	$ 35
Pension Plan [Member] | U.K. [Member] | North American Companies Equity Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					0.00%	1.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					1.00%
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					$ 3	$ 74
Pension Plan [Member] | U.K. [Member] | Emerging Markets Companies Equity Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					0.00%	0.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					1.00%
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					$ 1	$ 32
Pension Plan [Member] | U.K. [Member] | Global Equities Equity Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					23.00%	19.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					9.00%
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					$ 2,253	$ 1,684
Pension Plan [Member] | U.K. [Member] | Global Tactical Asset Allocation Equity Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					20.00%	29.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					41.00%
Pension Plan [Member] | U.K. [Member] | Other Equity Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					$ 1,950	$ 2,584
Pension Plan [Member] | U.K. [Member] | Debt Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					48.00%	43.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					38.00%
Pension Plan [Member] | U.K. [Member] | U.K. Corporate Bonds Debt Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					$ 574	$ 0
Measured at fair value not using net asset value per share					0	5
Pension Plan [Member] | U.K. [Member] | U.K. Corporate Bonds Debt Securities [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					0	0
Measured at fair value not using net asset value per share					0	0
Pension Plan [Member] | U.K. [Member] | U.K. Corporate Bonds Debt Securities [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					0	0
Measured at fair value not using net asset value per share					0	5
Pension Plan [Member] | U.K. [Member] | U.K. Corporate Bonds Debt Securities [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					0	0
Measured at fair value not using net asset value per share					0	0
Pension Plan [Member] | U.K. [Member] | U.K. Gilts Debt Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					4,209	3,819
Pension Plan [Member] | U.K. [Member] | U.K. Gilts Debt Securities [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Pension Plan [Member] | U.K. [Member] | U.K. Gilts Debt Securities [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					4,209	3,819
Pension Plan [Member] | U.K. [Member] | U.K. Gilts Debt Securities [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					$ 0	$ 0
Pension Plan [Member] | U.K. [Member] | Alternative Investments [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					5.00%	6.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					6.00%
Pension Plan [Member] | U.K. [Member] | Real Estate Alternative Investments [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					$ 557	$ 519
Pension Plan [Member] | U.K. [Member] | Total Trust Assets Prior to Adjustments [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	9,966	9,966	8,982	8,982	9,966	8,982
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	9,966		8,982
Balance at end of period		9,966	9,966	8,982
Pension Plan [Member] | U.K. [Member] | Receivables And Payables Net [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	4	4	(37)	(37)	$ 4	$ (37)
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	4		(37)
Balance at end of period		4	4	(37)
Other Postretirement Benefits Plan [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					100.00%	100.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					100.00%
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	367	367	367	301	$ 367	$ 340
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	367		340	301
Balance at end of period		367	367	340
Defined Benefit Plan Estimated Future Employer Contributions (Numeric) [Abstract]
Employer contributions			18	10
Amount to be contributed to plan in the next fiscal year					35
Estimated Future Benefit Payments (Details) [Abstract]
2021					49
2022					47
2023					46
2024					44
2025					43
2026-2030					194
Expected Federal Subsidy (Details) [Abstract]
Federal subsidy 2021					1
Federal subsidy 2022					0
Federal subsidy 2023					0
Federal subsidy 2024					0
Federal subsidy 2025					0
Federal subsidy 2026-2030					1
Other Postretirement Benefits Plan [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	5	5	6	6	5	6
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	5		6
Balance at end of period		5	5	6
Other Postretirement Benefits Plan [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	39	39	35	35	39	35
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	39		35
Balance at end of period		39	39	35
Other Postretirement Benefits Plan [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	0	0	0	0	$ 0	$ 0
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	0		0
Balance at end of period		0	$ 0	0
Other Postretirement Benefits Plan [Member] | Cash And Cash Equivalents [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					3.00%	3.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					5.00%
Other Postretirement Benefits Plan [Member] | Money Market Funds [Member]
Assumptions Used in Calculations (Numeric) [Abstract]
Number of months from date of purchase that investment must mature			13 months
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					$ 5	$ 6
Other Postretirement Benefits Plan [Member] | Money Market Funds [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					5	6
Other Postretirement Benefits Plan [Member] | Money Market Funds [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Other Postretirement Benefits Plan [Member] | Money Market Funds [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					$ 0	$ 0
Other Postretirement Benefits Plan [Member] | Equity Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					42.00%	45.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					45.00%
Other Postretirement Benefits Plan [Member] | United States Large Cap Equity Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					$ 89	$ 89
Other Postretirement Benefits Plan [Member] | Commingled Debt Equity Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					$ 77	$ 68
Other Postretirement Benefits Plan [Member] | Debt Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					55.00%	52.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					50.00%
Other Postretirement Benefits Plan [Member] | US Treasury And US Government Sponsored Agency Debt Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					$ 2	$ 0
Other Postretirement Benefits Plan [Member] | US Treasury And US Government Sponsored Agency Debt Securities [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Other Postretirement Benefits Plan [Member] | US Treasury And US Government Sponsored Agency Debt Securities [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					2	0
Other Postretirement Benefits Plan [Member] | US Treasury And US Government Sponsored Agency Debt Securities [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Other Postretirement Benefits Plan [Member] | Corporate Debt Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					37	35
Other Postretirement Benefits Plan [Member] | Corporate Debt Securities [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Other Postretirement Benefits Plan [Member] | Corporate Debt Securities [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					37	35
Other Postretirement Benefits Plan [Member] | Corporate Debt Securities [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Other Postretirement Benefits Plan [Member] | Total Trust Assets Prior to Adjustments [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	210	210	$ 198	198	210	198
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	210		198
Balance at end of period		210	210	198
Other Postretirement Benefits Plan [Member] | Receivables And Payables Net [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	(1)	(1)	0	0	(1)	0
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	(1)		0
Balance at end of period		(1)	(1)	0
Other Postretirement Benefits Plan [Member] | Account 401 H [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	158	158	142	142	158	142
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	158		142
Balance at end of period		158	158	142
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	1,668	1,668	1,470	1,470	1,668	$ 1,470
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	1,668		1,470	1,294
Balance at end of period		1,668	1,668	1,470
Defined Benefit Plan Estimated Future Employer Contributions (Numeric) [Abstract]
Employer contributions		23	$ 50	$ 24
Amount to be contributed to plan in the next fiscal year					0
Expected amount of benefit payments in the next period for non-qualified plans					6
Estimated Future Benefit Payments (Details) [Abstract]
2021					121
2022					119
2023					118
2024					117
2025					115
2026-2030					$ 533
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					100.00%	100.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					100.00%
Information About Plan Assets (Numeric) [Abstract]
Value of plan U.S. pension trust assets that relate to PPL subsidiary					$ 1,700	$ 1,500
Undivided interest percentage in each asset category that PPL subsidiary holds				41.00%
Assumptions Used in Calculations (Numeric) [Abstract]
The limited lives of four partnership of private equity investments (in years)			10 years
The amount of potential liability that maybe required to be funded by the master trust during life of the partnership					45
Number Of Days Notice Required To Redeem Shares			45 days
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	4,068	4,068	$ 3,585	$ 3,585	4,068	3,585
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	4,068		3,585
Balance at end of period		4,068	4,068	3,585
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	695	695	685	685	695	685
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	695		685
Balance at end of period		695	695	685
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	1,007	1,007	949	949	1,007	949
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	1,007		949
Balance at end of period		1,007	1,007	949
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	15	15	24	46	15	24
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	15		24	46
Actual return on plan assets relating to assets still held at the reporting date				3
Actual return on plan assets relating to assets sold during the period				3
Purchases, sales and settlements			(9)	(28)
Balance at end of period		15	15	24
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Cash And Cash Equivalents [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					300	182
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Cash And Cash Equivalents [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					300	182
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Cash And Cash Equivalents [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Cash And Cash Equivalents [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Equity Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					742	451
Measured at fair value not using net asset value per share					60	194
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Equity Securities [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					60	194
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Equity Securities [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Equity Securities [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | International Equity Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					566	554
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Commingled Debt Equity Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					712	621
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | US Treasury And US Government Sponsored Agency Debt Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					336	310
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | US Treasury And US Government Sponsored Agency Debt Securities [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					335	309
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | US Treasury And US Government Sponsored Agency Debt Securities [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					1	1
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | US Treasury And US Government Sponsored Agency Debt Securities [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Corporate Debt Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					1,045	951
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Corporate Debt Securities [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Corporate Debt Securities [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					1,030	931
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Corporate Debt Securities [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					15	20
Fair value at end of period	15	15	20	20	15	20
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	15		20	25
Actual return on plan assets relating to assets still held at the reporting date				(1)
Actual return on plan assets relating to assets sold during the period				3
Purchases, sales and settlements			(5)	(7)
Balance at end of period		15	15	20
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Other Debt Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					13	14
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Other Debt Securities [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Other Debt Securities [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					13	14
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Other Debt Securities [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Real Estate Alternative Investments [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					76	88
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Total Trust Assets Prior to Adjustments [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	4,110	4,110	3,628	3,628	4,110	3,628
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	4,110		3,628
Balance at end of period		4,110	4,110	3,628
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Private Equity Alternative Investments [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					68	62
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Hedge Fund Of Funds Alternative Investments [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					223	194
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Derivatives [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					(37)	3
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Derivatives [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Derivatives [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					(37)	3
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Derivatives [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Insurance Contracts [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	4
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Insurance Contracts [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Insurance Contracts [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Insurance Contracts [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	4
Fair value at end of period	0	0	0	21	0	4
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	0		4	21
Actual return on plan assets relating to assets still held at the reporting date				4
Actual return on plan assets relating to assets sold during the period				0
Purchases, sales and settlements			(4)	(21)
Balance at end of period		0	0	4
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Receivables And Payables Net [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	116	116	99	99	116	99
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	116		99
Balance at end of period		116	116	99
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Account 401 H [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	(158)	(158)	(142)	(142)	(158)	(142)
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	(158)		(142)
Balance at end of period		(158)	(158)	(142)
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Limited Partner
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					$ 6	$ 0
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Growth Portfolio [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					56.00%	57.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					55.00%
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Growth Portfolio [Member] | Equity Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					34.00%	34.00%
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Growth Portfolio [Member] | Debt Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					13.00%	14.00%
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Growth Portfolio [Member] | Alternative Investments [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					9.00%	9.00%
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Immunizing Portfolio [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					43.00%	42.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					43.00%
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Immunizing Portfolio [Member] | Debt Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					33.00%	35.00%
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Immunizing Portfolio [Member] | Derivatives [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					10.00%	7.00%
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Liquidity Portfolio [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					1.00%	1.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					2.00%
LG And E And KU Energy LLC [Member] | Other Postretirement Benefits Plan [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	160	160	141	141	$ 160	$ 141
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	160		141	117
Balance at end of period		160	160	141
Defined Benefit Plan Estimated Future Employer Contributions (Numeric) [Abstract]
Employer contributions			4	11
Amount to be contributed to plan in the next fiscal year					15
Estimated Future Benefit Payments (Details) [Abstract]
2021					15
2022					16
2023					16
2024					16
2025					16
2026-2030					75
Expected Federal Subsidy (Details) [Abstract]
Federal subsidy 2021					1
Federal subsidy 2022					0
Federal subsidy 2023					0
Federal subsidy 2024					0
Federal subsidy 2025					0
Federal subsidy 2026-2030					$ 1
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period			310	310		$ 310
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period			$ 310	281
Balance at end of period				310
Defined Benefit Plan Estimated Future Employer Contributions (Numeric) [Abstract]
Employer contributions				$ 1
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					100.00%	100.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					100.00%
Information About Plan Assets (Numeric) [Abstract]
Value of plan U.S. pension trust assets that relate to PPL subsidiary						$ 310
Undivided interest percentage in each asset category that PPL subsidiary holds			9.00%	9.00%
Assumptions Used in Calculations (Numeric) [Abstract]
The limited lives of four partnership of private equity investments (in years)			10 years
The amount of potential liability that maybe required to be funded by the master trust during life of the partnership					$ 45
Number Of Days Notice Required To Redeem Shares			45 days
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	4,068	4,068	$ 3,585	$ 3,585	4,068	3,585
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	4,068		3,585
Balance at end of period		4,068	4,068	3,585
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Parent [Member]
Information About Plan Assets (Numeric) [Abstract]
Value of plan U.S. pension trust assets that relate to PPL subsidiary					618	251
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	695	695	685	685	695	685
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	695		685
Balance at end of period		695	695	685
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	1,007	1,007	949	949	1,007	949
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	1,007		949
Balance at end of period		1,007	1,007	949
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	15	15	24	46	15	24
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	15		24	46
Actual return on plan assets relating to assets still held at the reporting date				3
Actual return on plan assets relating to assets sold during the period				3
Purchases, sales and settlements			(9)	(28)
Balance at end of period		15	15	24
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Cash And Cash Equivalents [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					300	182
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Cash And Cash Equivalents [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					300	182
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Cash And Cash Equivalents [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Cash And Cash Equivalents [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Equity Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					742	451
Measured at fair value not using net asset value per share					60	194
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Equity Securities [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					60	194
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Equity Securities [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Equity Securities [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | International Equity Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					566	554
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Commingled Debt Equity Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					712	621
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | US Treasury And US Government Sponsored Agency Debt Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					336	310
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | US Treasury And US Government Sponsored Agency Debt Securities [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					335	309
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | US Treasury And US Government Sponsored Agency Debt Securities [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					1	1
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | US Treasury And US Government Sponsored Agency Debt Securities [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Corporate Debt Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					1,045	951
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Corporate Debt Securities [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Corporate Debt Securities [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					1,030	931
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Corporate Debt Securities [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					15	20
Fair value at end of period	15	15	20	20	15	20
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	15		20	25
Actual return on plan assets relating to assets still held at the reporting date				(1)
Actual return on plan assets relating to assets sold during the period				3
Purchases, sales and settlements			(5)	(7)
Balance at end of period		15	15	20
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Other Debt Securities [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					13	14
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Other Debt Securities [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Other Debt Securities [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					13	14
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Other Debt Securities [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Real Estate Alternative Investments [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					76	88
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Total Trust Assets Prior to Adjustments [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	4,110	4,110	3,628	3,628	4,110	3,628
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	4,110		3,628
Balance at end of period		4,110	4,110	3,628
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Private Equity Alternative Investments [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					68	62
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Hedge Fund Of Funds Alternative Investments [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					223	194
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Derivatives [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					(37)	3
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Derivatives [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Derivatives [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					(37)	3
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Derivatives [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Insurance Contracts [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	4
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Insurance Contracts [Member] | Level 1 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Insurance Contracts [Member] | Level 2 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	0
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Insurance Contracts [Member] | Level 3 [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value not using net asset value per share					0	4
Fair value at end of period	0	0	0	21	0	4
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	0		4	21
Actual return on plan assets relating to assets still held at the reporting date				4
Actual return on plan assets relating to assets sold during the period				0
Purchases, sales and settlements			(4)	(21)
Balance at end of period		0	0	4
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Receivables And Payables Net [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	116	116	99	99	116	99
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	116		99
Balance at end of period		116	116	99
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Account 401 H [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	(158)	(158)	(142)	(142)	(158)	(142)
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	$ (158)		(142)
Balance at end of period		$ (158)	$ (158)	$ (142)
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Limited Partner
Defined benefit plan fair value of plan assets (Details) [Abstract]
Measured at fair value using net asset value per share					$ 6	$ 0
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Growth Portfolio [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					56.00%	57.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					55.00%
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Growth Portfolio [Member] | Equity Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					34.00%	34.00%
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Growth Portfolio [Member] | Debt Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					13.00%	14.00%
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Growth Portfolio [Member] | Alternative Investments [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					9.00%	9.00%
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Immunizing Portfolio [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					43.00%	42.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					43.00%
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Immunizing Portfolio [Member] | Debt Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					33.00%	35.00%
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Immunizing Portfolio [Member] | Derivatives [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					10.00%	7.00%
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Liquidity Portfolio [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets					1.00%	1.00%
Target Allocations (Details ) [Abstract]
Target asset allocation					2.00%
Kentucky Utilities Co [Member] | Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Parent [Member]
Information About Plan Assets (Numeric) [Abstract]
Value of plan U.S. pension trust assets that relate to PPL subsidiary					$ 505	$ 445