Pension and Other Postretirement Plans - Pension and Other Postretirement Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Level 3
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	$ 333	$ 435	$ 401
Pension Benefits
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	3,467	4,626	4,069
Pension Benefits | Level 1
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	64	179
Pension Benefits | Level 2
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	569	842
Pension Benefits | Level 3
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	285	386
Pension Benefits | Assets Measured at NAV
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	2,549	3,219
Pension Benefits | Equity securities funds
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	1,183	1,754
Pension Benefits | Equity securities funds | Level 1
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	58	71
Pension Benefits | Equity securities funds | Level 2
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	26	44
Pension Benefits | Equity securities funds | Level 3
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	114	147
Pension Benefits | Equity securities funds | Assets Measured at NAV
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	985	1,492
Pension Benefits | Fixed-income securities
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	1,316	1,850
Pension Benefits | Fixed-income securities | Level 1
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Fixed-income securities | Level 2
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	527	739
Pension Benefits | Fixed-income securities | Level 3
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	5	15
Pension Benefits | Fixed-income securities | Assets Measured at NAV
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	784	1,096
Pension Benefits | Alternatives
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	887	847
Pension Benefits | Alternatives | Level 1
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Alternatives | Level 2
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Alternatives | Level 3
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	161	216
Pension Benefits | Alternatives | Assets Measured at NAV
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	726	631
Pension Benefits | Other investments
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	81	175
Pension Benefits | Other investments | Level 1
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	6	108
Pension Benefits | Other investments | Level 2
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	16	59
Pension Benefits | Other investments | Level 3
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	5	8
Pension Benefits | Other investments | Assets Measured at NAV
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	54	0
Other Postretirement Benefits
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	48	49	$ 51
Other Postretirement Benefits | Deposit administration fund
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	48	49
Other Postretirement Benefits | Deposit administration fund | Level 1
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Deposit administration fund | Level 2
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	0	0
Other Postretirement Benefits | Deposit administration fund | Level 3
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	48	49
Other Postretirement Benefits | Deposit administration fund | Assets Measured at NAV
Defined Benefit Plan, Plan Assets, Category [Line Items]
Fair value of plan assets	$ 0	$ 0