Retirement and Postemployment Benefits (Plan Assets and Expected Cash Flows) (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Pension Plan [Member] | U.S. [Member]
Defined benefit plan fair value of plan assets (Details) [Abstract]
Fair value at end of period	$ 3,585	$ 3,585	$ 3,488	$ 3,585	$ 3,109
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	3,585	3,109	3,488
Balance at end of period		3,585	3,109
Defined Benefit Plan Estimated Future Employer Contributions (Numeric) [Abstract]
Employer contributions		$ 63	153
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				9
Estimated Future Benefit Payments (Details) [Abstract]
2020				271
2021				267
2022				266
2023				264
2024				265
2025-2029				$ 1,278
Pension Plan [Member] | U.S. [Member] | Subsequent Event [Member]
Defined Benefit Plan Estimated Future Employer Contributions (Numeric) [Abstract]
Employer contributions	52
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				$ 63
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	3,585	$ 3,109	3,109	3,585	$ 3,109
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	3,585	3,109
Balance at end of period		3,585	3,109
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	685	591	591	685	591
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	685	591
Balance at end of period		685	591
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	949	924	924	949	924
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	949	924
Balance at end of period		949	924
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	24	46	46	24	46
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	24	46	37
Actual return on plan assets relating to assets still held at the reporting date		3	(1)
Actual return on plan assets relating to assets sold during the period		3	3
Purchases, sales and settlements		(28)	7
Balance at end of period		24	46
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				182	220
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				182	220
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				451	340
Measured at fair value not using net asset value per share				194	159
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				194	159
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				554	466
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				621	543
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				310	212
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				309	212
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	0
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				951	899
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				931	874
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				20	25
Fair value at end of period	20	20	13	20	25
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	20	25	13
Actual return on plan assets relating to assets still held at the reporting date		(1)	(2)
Actual return on plan assets relating to assets sold during the period		3	3
Purchases, sales and settlements		(7)	11
Balance at end of period		20	25
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				14	17
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				14	17
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				88	90
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	3,628	3,240	3,240	3,628	3,240
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	3,628	3,240
Balance at end of period		3,628	3,240
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				62	65
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				194	175
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				3	33
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				3	33
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				4	21
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				4	21
Fair value at end of period	4	21	21	4	21
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	4	21	24
Actual return on plan assets relating to assets still held at the reporting date		4	1
Actual return on plan assets relating to assets sold during the period		0	0
Purchases, sales and settlements		(21)	(4)
Balance at end of period		4	21
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	99	(2)	(2)	99	(2)
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	99	(2)
Balance at end of period		99	(2)
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	(142)	(129)	(129)	$ (142)	$ (129)
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	(142)	(129)
Balance at end of period		(142)	(129)
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Growth Portfolio [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets				57.00%	55.00%
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%	30.00%
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				14.00%	15.00%
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%	10.00%
Pension Plan [Member] | U.S. [Member] | Master Trust [Member] | Immunizing Portfolio [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets				42.00%	43.00%
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				35.00%	39.00%
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				7.00%	4.00%
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%	2.00%
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	8,945	7,801	7,801	$ 8,945	$ 7,801
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	8,945	7,801	8,490
Balance at end of period		8,945	7,801
Defined Benefit Plan Estimated Future Employer Contributions (Numeric) [Abstract]
Employer contributions		$ 278	188
Amount to be contributed to plan in the next fiscal year				273
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]
2020				353
2021				351
2022				356
2023				359
2024				364
2025-2029				1,826
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	154	$ 147	147	154	147
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	154	147
Balance at end of period		154	147
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	3,824	2,937	2,937	3,824	2,937
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	3,824	2,937
Balance at end of period		3,824	2,937
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
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
Pension Plan [Member] | U.K. [Member] | Cash And Cash Equivalents [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets				2.00%	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				$ 154	$ 147
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				154	147
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				$ 22	$ 27
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%	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				$ 54	$ 76
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%	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				$ 35	$ 49
Pension Plan [Member] | U.K. [Member] | North American Companies Equity Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets				1.00%	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				$ 74	$ 105
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%	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				$ 32	$ 44
Pension Plan [Member] | U.K. [Member] | Global Equities Equity Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets				19.00%	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				$ 1,684	$ 1,465
Pension Plan [Member] | U.K. [Member] | Global Tactical Asset Allocation Equity Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets				29.00%	31.00%
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				$ 2,584	$ 2,437
Pension Plan [Member] | U.K. [Member] | Debt Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets				43.00%	38.00%
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 not using net asset value per share				$ 5	$ 4
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 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 not using net asset value per share				5	4
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 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				3,819	2,933
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				3,819	2,933
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				6.00%	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				$ 519	$ 485
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	8,982	7,772	7,772	8,982	7,772
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	8,982	7,772
Balance at end of period		8,982	7,772
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	(37)	29	29	$ (37)	$ 29
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	(37)	29
Balance at end of period		(37)	29
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	340	301	301	$ 340	$ 301
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	340	301	405
Balance at end of period		340	301
Defined Benefit Plan Estimated Future Employer Contributions (Numeric) [Abstract]
Employer contributions		10	23
Amount to be contributed to plan in the next fiscal year				14
Estimated Future Benefit Payments (Details) [Abstract]
2020				50
2021				48
2022				47
2023				46
2024				44
2025-2029				200
Expected Federal Subsidy (Details) [Abstract]
Federal subsidy 2020				1
Federal subsidy 2021				1
Federal subsidy 2022				0
Federal subsidy 2023				0
Federal subsidy 2024				0
Federal subsidy 2025-2029				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	6	6	6	6	6
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	6	6
Balance at end of period		6	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	35	28	28	35	28
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	35	28
Balance at end of period		35	28
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
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
Other Postretirement Benefits Plan [Member] | Cash And Cash Equivalents [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets				3.00%	4.00%
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				$ 6	$ 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				6	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				45.00%	40.00%
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	$ 69
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				$ 68	$ 68
Other Postretirement Benefits Plan [Member] | Debt Securities [Member]
Actual Allocation by Plan Asset (Details) [Abstract]
Percentage of trust assets				52.00%	56.00%
Target Allocations (Details ) [Abstract]
Target asset allocation				50.00%
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				$ 35	$ 28
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				35	28
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	198	$ 171	171	198	171
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	198	171
Balance at end of period		198	171
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	0	1	1	0	1
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	0	1
Balance at end of period		0	1
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	142	129	129	142	129
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	142	129
Balance at end of period		142	129
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	1,470	1,470	1,402	1,470	$ 1,294
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	1,470	1,294	1,402
Balance at end of period		1,470	1,294
Defined Benefit Plan Estimated Future Employer Contributions (Numeric) [Abstract]
Employer contributions		$ 24	$ 109
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				5
Estimated Future Benefit Payments (Details) [Abstract]
2020				114
2021				115
2022				115
2023				113
2024				115
2025-2029				$ 545
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. [Member] | Subsequent Event [Member]
Defined Benefit Plan Estimated Future Employer Contributions (Numeric) [Abstract]
Employer contributions	22
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				$ 1,500	$ 1,300
Undivided interest percentage in each asset category that PPL subsidiary holds		41.00%	42.00%
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				63
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	3,585	$ 3,585	$ 3,109	3,585	3,109
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	3,585	3,109
Balance at end of period		3,585	3,109
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	685	685	591	685	591
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	685	591
Balance at end of period		685	591
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	949	949	924	949	924
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	949	924
Balance at end of period		949	924
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	24	24	46	24	46
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	24	46	37
Actual return on plan assets relating to assets still held at the reporting date		3	(1)
Actual return on plan assets relating to assets sold during the period		3
Purchases, sales and settlements		(28)	7
Balance at end of period		24	46
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				182	220
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				182	220
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				451	340
Measured at fair value not using net asset value per share				194	159
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				194	159
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				554	466
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				621	543
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				310	212
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				309	212
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	0
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				951	899
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				931	874
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				20	25
Fair value at end of period	20	20	25	20	25
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	20	25	13
Actual return on plan assets relating to assets still held at the reporting date		(1)	(2)
Actual return on plan assets relating to assets sold during the period		3
Purchases, sales and settlements		(7)	11
Balance at end of period		20	25
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				14	17
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				14	17
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				88	90
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	3,628	3,628	3,240	3,628	3,240
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	3,628	3,240
Balance at end of period		3,628	3,240
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				62	65
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				194	175
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				3	33
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				3	33
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				4	21
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				4	21
Fair value at end of period	4	4	21	4	21
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	4	21	24
Actual return on plan assets relating to assets still held at the reporting date		4	1
Actual return on plan assets relating to assets sold during the period		0
Purchases, sales and settlements		(21)	(4)
Balance at end of period		4	21
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	99	99	(2)	99	(2)
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	99	(2)
Balance at end of period		99	(2)
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	(142)	(142)	(129)	$ (142)	$ (129)
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	(142)	(129)
Balance at end of period		(142)	(129)
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				57.00%	55.00%
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%	30.00%
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				14.00%	15.00%
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%	10.00%
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				42.00%	43.00%
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				35.00%	39.00%
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				7.00%	4.00%
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%	2.00%
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	141	141	116	$ 141	$ 117
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	141	117	116
Balance at end of period		141	117
Defined Benefit Plan Estimated Future Employer Contributions (Numeric) [Abstract]
Employer contributions		11	24
Amount to be contributed to plan in the next fiscal year				14
Estimated Future Benefit Payments (Details) [Abstract]
2020				14
2021				15
2022				15
2023				15
2024				15
2025-2029				72
Expected Federal Subsidy (Details) [Abstract]
Federal subsidy 2020				1
Federal subsidy 2021				0
Federal subsidy 2022				0
Federal subsidy 2023				0
Federal subsidy 2024				0
Federal subsidy 2025-2029				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	281	281	$ 310	$ 281
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	310	281	325
Balance at end of period		310	281
Defined Benefit Plan Estimated Future Employer Contributions (Numeric) [Abstract]
Employer contributions		$ 1	$ 10
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	$ 281
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				63
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	3,585	$ 3,585	$ 3,109	3,585	3,109
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	3,585	3,109
Balance at end of period		3,585	3,109
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	685	685	591	685	591
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	685	591
Balance at end of period		685	591
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	949	949	924	949	924
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	949	924
Balance at end of period		949	924
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	24	24	46	24	46
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	24	46	37
Actual return on plan assets relating to assets still held at the reporting date		3	(1)
Actual return on plan assets relating to assets sold during the period		3
Purchases, sales and settlements		(28)	7
Balance at end of period		24	46
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				182	220
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				182	220
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				451	340
Measured at fair value not using net asset value per share				194	159
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				194	159
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				554	466
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				621	543
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				310	212
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				309	212
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	0
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				951	899
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				931	874
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				20	25
Fair value at end of period	20	20	25	20	25
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	20	25	13
Actual return on plan assets relating to assets still held at the reporting date		(1)	(2)
Actual return on plan assets relating to assets sold during the period		3
Purchases, sales and settlements		(7)	11
Balance at end of period		20	25
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				14	17
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				14	17
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				88	90
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	3,628	3,628	3,240	3,628	3,240
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	3,628	3,240
Balance at end of period		3,628	3,240
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				62	65
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				194	175
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				3	33
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				3	33
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				4	21
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				4	21
Fair value at end of period	4	4	21	4	21
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	4	21	24
Actual return on plan assets relating to assets still held at the reporting date		4	1
Actual return on plan assets relating to assets sold during the period		0
Purchases, sales and settlements		(21)	(4)
Balance at end of period		4	21
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	99	99	(2)	99	(2)
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	99	(2)
Balance at end of period		99	(2)
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	(142)	(142)	(129)	$ (142)	$ (129)
Change in Fair Value of Level 3 Plan Assets [Roll Forward]
Balance at beginning of period	$ (142)	(129)
Balance at end of period		$ (142)	$ (129)
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				57.00%	55.00%
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%	30.00%
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				14.00%	15.00%
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%	10.00%
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				42.00%	43.00%
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				35.00%	39.00%
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				7.00%	4.00%
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%	2.00%
Target Allocations (Details ) [Abstract]
Target asset allocation				2.00%