Pension and Other Postretirement Benefit Plans - Fair Values of Other Postretirement Benefit Plan Assets (Details) - Other Postretirement Benefits - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	$ 947	$ 1,292	$ 1,221
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	10	39
Developed markets equities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	279	402
Emerging markets equities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	74	92
Government and agency obligations
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	1	1
Real estate
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	14	0
Developed markets
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	206	290
Government and agency obligations
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	212	275
Corporate obligations
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	137	191
Mortgage and asset-backed securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	2	2
Derivatives
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	12	0
Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	231	326
Level 1 | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	2	11
Level 1 | Developed markets equities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	22	24
Level 1 | Emerging markets equities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 1 | Government and agency obligations
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	1	1
Level 1 | Real estate
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 1 | Developed markets
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	206	290
Level 1 | Government and agency obligations
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 1 | Corporate obligations
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 1 | Mortgage and asset-backed securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 1 | Derivatives
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	363	468
Level 2 | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 2 | Developed markets equities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 2 | Emerging markets equities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 2 | Government and agency obligations
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 2 | Real estate
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 2 | Developed markets
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 2 | Government and agency obligations
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	212	275
Level 2 | Corporate obligations
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	137	191
Level 2 | Mortgage and asset-backed securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	2	2
Level 2 | Derivatives
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	12	0
Level 3
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 3 | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 3 | Developed markets equities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 3 | Emerging markets equities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 3 | Government and agency obligations
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 3 | Real estate
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 3 | Developed markets
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 3 | Government and agency obligations
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 3 | Corporate obligations
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 3 | Mortgage and asset-backed securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
Level 3 | Derivatives
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
NAV
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	353	498
NAV | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	8	28
NAV | Developed markets equities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	257	378
NAV | Emerging markets equities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	74	92
NAV | Government and agency obligations
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
NAV | Real estate
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	14	0
NAV | Developed markets
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
NAV | Government and agency obligations
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
NAV | Corporate obligations
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
NAV | Mortgage and asset-backed securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	0
NAV | Derivatives
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	$ 0	$ 0