Employee Benefit Plans - Unrecognized Amounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Pension | United States
Defined Benefit Plan Disclosure [Line Items]
Net loss (gain)	$ 343	$ 612
Prior service credit	(1)	(1)
Regulatory deferrals	11	2
Total	353	613
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	613	652
Net (gain) loss arising during the year	(231)	(7)
Settlement	(4)
Net amortization	(25)	(32)
Total	(260)	(39)
Ending balance	353	613
Pension | United States | Accumulated Other Comprehensive Income (Loss)
Defined Benefit Plan Disclosure [Line Items]
Total	22	33
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	33	24
Net (gain) loss arising during the year	(10)	10
Settlement	0
Net amortization	(1)	(1)
Total	(11)	9
Ending balance	22	33
Pension | United States | Regulatory Asset
Defined Benefit Plan Disclosure [Line Items]
Total	390	600
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	600	661
Net (gain) loss arising during the year	(177)	(30)
Settlement	(9)
Net amortization	(24)	(31)
Total	(210)	(61)
Ending balance	390	600
Pension | United States | Regulatory Liability
Defined Benefit Plan Disclosure [Line Items]
Total	(59)	(20)
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	(20)	(33)
Net (gain) loss arising during the year	(44)	13
Settlement	5
Net amortization	0	0
Total	(39)	13
Ending balance	(59)	(20)
Pension | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Net loss	400	612
Prior service cost	5	6
Total	405	618
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	618
Ending balance	405	618
Pension | United Kingdom | Accumulated Other Comprehensive Income (Loss)
Defined Benefit Plan Disclosure [Line Items]
Total	405	618
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	618	549
Net (gain) loss arising during the year	(143)	108
Settlement	(10)	(17)
Net amortization	(55)	(43)
Foreign currency exchange rate changes	(5)	21
Total	(213)	69
Ending balance	405	618
Other Postretirement
Defined Benefit Plan Disclosure [Line Items]
Net loss (gain)	(34)	34
Prior service credit	(1)	(9)
Regulatory deferrals	2	3
Total	(33)	28
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	28	(31)
Net (gain) loss arising during the year	(65)	55
Net prior service credit arising during the year	1
Net amortization	3	4
Total	(61)	59
Ending balance	(33)	28
Other Postretirement | Accumulated Other Comprehensive Income (Loss)
Defined Benefit Plan Disclosure [Line Items]
Total	1	4
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	4	(3)
Net (gain) loss arising during the year	(3)	7
Net prior service credit arising during the year	0
Net amortization	0	0
Total	(3)	7
Ending balance	1	4
Other Postretirement | Regulatory Asset
Defined Benefit Plan Disclosure [Line Items]
Total	11	47
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	47	4
Net (gain) loss arising during the year	(40)	36
Net prior service credit arising during the year	1
Net amortization	3	7
Total	(36)	43
Ending balance	11	47
Other Postretirement | Regulatory Liability
Defined Benefit Plan Disclosure [Line Items]
Total	(45)	(23)
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	(23)	(32)
Net (gain) loss arising during the year	(22)	12
Net prior service credit arising during the year	0
Net amortization	0	(3)
Total	(22)	9
Ending balance	$ (45)	$ (23)