Employee Benefit Plans - PAC - Unrecognized Amounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Other Postretirement
Defined Benefit Plan Disclosure [Line Items]
Net loss (gain)	$ (34)	$ 34
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 amortization	3	4
Total	(61)	59
Ending balance	(33)	28
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 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 amortization	0	(3)
Total	(22)	9
Ending balance	(45)	(23)
Other Postretirement | PAC
Defined Benefit Plan Disclosure [Line Items]
Net loss (gain)	(28)	(13)
Regulatory deferrals	2	3
Total	(26)	(10)
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	(10)
Ending balance	(26)	(10)
Other Postretirement | PAC | Regulatory Liability
Defined Benefit Plan Disclosure [Line Items]
Total	(26)	(10)
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	(10)	(20)
Net (gain) loss arising during the year	(15)	13
Net amortization	(1)	(3)
Total	(16)	10
Ending balance	(26)	(10)
United States | Pension
Defined Benefit Plan Disclosure [Line Items]
Net loss (gain)	343	612
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)
Net amortization	(25)	(32)
Settlement	(4)
Total	(260)	(39)
Ending balance	353	613
United States | Pension | 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)
Net amortization	(24)	(31)
Settlement	(9)
Total	(210)	(61)
Ending balance	390	600
United States | Pension | 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
Net amortization	0	0
Settlement	5
Total	(39)	13
Ending balance	(59)	(20)
United States | Pension | PAC
Defined Benefit Plan Disclosure [Line Items]
Net loss (gain)	298	455
Regulatory deferrals	11	2
Total	309	457
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	457	443
Net (gain) loss arising during the year	(121)	32
Net amortization	(21)	(18)
Settlement	(6)
Total	(148)	14
Ending balance	309	457
Regulatory deferrals, settlement losses	9
United States | Pension | PAC | Regulatory Asset
Defined Benefit Plan Disclosure [Line Items]
Total	286	432
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	432	422
Net (gain) loss arising during the year	(120)	27
Net amortization	(20)	(17)
Settlement	(6)
Total	(146)	10
Ending balance	286	432
United States | Pension | PAC | Accumulated Other Comprehensive Income (Loss)
Defined Benefit Plan Disclosure [Line Items]
Total	23	25
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	25	21
Net (gain) loss arising during the year	(1)	5
Net amortization	(1)	(1)
Settlement	0
Total	(2)	4
Ending balance	$ 23	$ 25