Other Postretirement Benefits - Schedule of Fair Values of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	$ 459	$ 525
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	860	1,150	$ 1,115	$ 1,026
Other Postretirement Benefits | Fair Value, Inputs, Level 1 and 2 | Total investments
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	649	875
Other Postretirement Benefits | Fair Value, Inputs, Level 1 and 2 | Equity
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	339	474
Other Postretirement Benefits | Fair Value, Inputs, Level 1 and 2 | Other Fixed Income Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	285	379
Other Postretirement Benefits | Fair Value, Inputs, Level 1 and 2 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	25	22
Other Postretirement Benefits | Fair Value, Inputs, Level 1 and 2 | Funds For Retiree Health Benefits
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	139	210
Other Postretirement Benefits | Fair Value, Inputs, Level 1 and 2 | Investments, Including Funds For Retiree Health Benefit
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	788	1,085
Other Postretirement Benefits | Fair Value, Inputs, Level 1 and 2 | Funds For Retiree Health Benefits Measured At Net Asset Value
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	51	48
Other Postretirement Benefits | Fair Value, Inputs, Level 1 and 2 | Pending Activities
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	21	17
Other Postretirement Benefits | Level 1 | Total investments
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	10	0
Other Postretirement Benefits | Level 1 | Equity
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	0	0
Other Postretirement Benefits | Level 1 | Other Fixed Income Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	10	0
Other Postretirement Benefits | Level 1 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	0	0
Other Postretirement Benefits | Level 1 | Funds For Retiree Health Benefits
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	48	110
Other Postretirement Benefits | Level 1 | Investments, Including Funds For Retiree Health Benefit
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	58	110
Other Postretirement Benefits | Level 2 | Total investments
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	639	875
Other Postretirement Benefits | Level 2 | Equity
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	339	474
Other Postretirement Benefits | Level 2 | Other Fixed Income Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	275	379
Other Postretirement Benefits | Level 2 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	25	22
Other Postretirement Benefits | Level 2 | Funds For Retiree Health Benefits
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	91	100
Other Postretirement Benefits | Level 2 | Investments, Including Funds For Retiree Health Benefit
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	$ 730	$ 975