Employee Benefit Plans - MEC - Unrecognized Amounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension | MEC
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Settlement	$ (4)	$ 5
Other Postretirement
Defined Benefit Plan Disclosure [Line Items]
Net loss (gain)	(38)	(34)
Prior service (credit) cost	21	(1)
Total	(16)	(33)	$ 28
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	(33)	28
Net loss (gain) arising during the year	(4)	(65)
Settlement	0	0	0
Net amortization	1	3
Total	17	(61)
Ending balance	(16)	(33)	28
Other Postretirement | Regulatory Asset
Defined Benefit Plan Disclosure [Line Items]
Total	45	11	47
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	11	47
Net loss (gain) arising during the year	20	(40)
Net amortization	3	3
Total	34	(36)
Ending balance	45	11	47
Other Postretirement | Regulatory Liability
Defined Benefit Plan Disclosure [Line Items]
Total	(59)	(45)	(23)
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	(45)	(23)
Net loss (gain) arising during the year	(20)	(22)
Net amortization	(2)	0
Total	(14)	(22)
Ending balance	(59)	(45)	(23)
Other Postretirement | MEC
Defined Benefit Plan Disclosure [Line Items]
Net loss (gain)	11	2
Prior service (credit) cost	19	(3)
Total	30	(1)	36
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	(1)	36
Net loss (gain) arising during the year	9	(42)
Net prior service credit arising during the year	19	1
Settlement	0	0	0
Net amortization	3	4
Total	31	(37)
Ending balance	30	(1)	36
Other Postretirement | MEC | Regulatory Asset
Defined Benefit Plan Disclosure [Line Items]
Total	33	20	45
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	20	45
Net loss (gain) arising during the year	10	(29)
Net prior service credit arising during the year	0	1
Net amortization	3	3
Total	13	(25)
Ending balance	33	20	45
Other Postretirement | MEC | Receivables (Payables) With Affiliates
Defined Benefit Plan Disclosure [Line Items]
Total	(3)	(21)	(9)
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	(21)	(9)
Net loss (gain) arising during the year	(1)	(13)
Net prior service credit arising during the year	19	0
Net amortization	0	1
Total	18	(12)
Ending balance	(3)	(21)	(9)
U.S. | Pension
Defined Benefit Plan Disclosure [Line Items]
Net loss (gain)	365	343
Prior service (credit) cost	(4)	(1)
Total	390	353	613
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	353	613
Net loss (gain) arising during the year	76	(231)
Settlement	(17)	(3)	0
Net amortization	(19)	(25)
Total	37	(260)
Ending balance	390	353	613
U.S. | Pension | Regulatory Asset
Defined Benefit Plan Disclosure [Line Items]
Total	418	390	600
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	390	600
Net loss (gain) arising during the year	58	(177)
Net amortization	(17)	(24)
Total	28	(210)
Ending balance	418	390	600
U.S. | Pension | Regulatory Liability
Defined Benefit Plan Disclosure [Line Items]
Total	(28)	(59)	(20)
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	(59)	(20)
Net loss (gain) arising during the year	38	(44)
Net amortization	0	0
Total	31	(39)
Ending balance	(28)	(59)	(20)
U.S. | Pension | MEC
Defined Benefit Plan Disclosure [Line Items]
Net loss (gain)	(4)	(25)
Prior service (credit) cost	(3)	0
Total	(7)	(25)	18
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	(25)	18
Net loss (gain) arising during the year	26	(47)
Net prior service credit arising during the year	(3)
Settlement	(4)	5	0
Net amortization	(1)	(1)
Total	18	(43)
Ending balance	(7)	(25)	18
U.S. | Pension | MEC | Regulatory Asset
Defined Benefit Plan Disclosure [Line Items]
Total	14	22	21
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	22	21
Net loss (gain) arising during the year	(7)	2
Net prior service credit arising during the year	0
Settlement	0	0
Net amortization	(1)	(1)
Total	(8)	1
Ending balance	14	22	21
U.S. | Pension | MEC | Regulatory Liability
Defined Benefit Plan Disclosure [Line Items]
Total	(1)	(55)	(20)
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	(55)	(20)
Net loss (gain) arising during the year	58	(40)
Net prior service credit arising during the year	0
Settlement	(4)	5
Net amortization	0	0
Total	54	(35)
Ending balance	(1)	(55)	(20)
U.S. | Pension | MEC | Receivables (Payables) With Affiliates
Defined Benefit Plan Disclosure [Line Items]
Total	(20)	8	17
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Beginning balance	8	17
Net loss (gain) arising during the year	(25)	(9)
Net prior service credit arising during the year	(3)
Settlement	0	0
Net amortization	0	0
Total	(28)	(9)
Ending balance	$ (20)	$ 8	$ 17