Pensions and Other Benefits - Pension Plan and Other Plan Assets Carried at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	$ 5,632	$ 6,035	$ 5,406
Pension Benefits | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	730	708
Pension Benefits | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	2,161	2,278
Pension Benefits | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	54	324
Pension Benefits | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	2,687	2,725
Pension Benefits | Equity
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	616	483
Pension Benefits | Equity | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	616	483
Pension Benefits | Equity | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Equity | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Equity | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | U. S. companies
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	433	306
Pension Benefits | U. S. companies | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	433	306
Pension Benefits | U. S. companies | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | U. S. companies | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | U. S. companies | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | International companies
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	183	177
Pension Benefits | International companies | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	183	177
Pension Benefits | International companies | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | International companies | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | International companies | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	2,161	2,278
Pension Benefits | Fixed Income | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Fixed Income | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	2,161	2,278
Pension Benefits | Fixed Income | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Fixed Income | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Corporate Bonds - U.S.
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	1,405	1,514
Pension Benefits | Corporate Bonds - U.S. | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Corporate Bonds - U.S. | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	1,405	1,514
Pension Benefits | Corporate Bonds - U.S. | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Corporate Bonds - U.S. | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Corporate Bonds - Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	251	252
Pension Benefits | Corporate Bonds - Non-U.S. | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Corporate Bonds - Non-U.S. | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	251	252
Pension Benefits | Corporate Bonds - Non-U.S. | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Corporate Bonds - Non-U.S. | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | U.S. government and agencies
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	426	202
Pension Benefits | U.S. government and agencies | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | U.S. government and agencies | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	426	202
Pension Benefits | U.S. government and agencies | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | U.S. government and agencies | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Non-U.S. government
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	78	97
Pension Benefits | Non-U.S. government | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Non-U.S. government | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	78	97
Pension Benefits | Non-U.S. government | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Non-U.S. government | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Mortgage and asset-backed securities
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	1	213
Pension Benefits | Mortgage and asset-backed securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Mortgage and asset-backed securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	1	213
Pension Benefits | Mortgage and asset-backed securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Mortgage and asset-backed securities | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Alternatives
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	777	760
Pension Benefits | Alternatives | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Alternatives | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Alternatives | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	54	324
Pension Benefits | Alternatives | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	723	436
Pension Benefits | Timberlands
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	268	269
Pension Benefits | Timberlands | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Timberlands | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Timberlands | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	269
Pension Benefits | Timberlands | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	268	0
Pension Benefits | Mineral Interests and other alternatives
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	31	19
Pension Benefits | Mineral Interests and other alternatives | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Mineral Interests and other alternatives | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Mineral Interests and other alternatives | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	22	19
Pension Benefits | Mineral Interests and other alternatives | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	9	0
Pension Benefits | Private equity
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	259	231
Pension Benefits | Private equity | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Private equity | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Private equity | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Private equity | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	259	231
Pension Benefits | Real estate
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	219	241
Pension Benefits | Real estate | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Real estate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Real estate | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	32	36
Pension Benefits | Real estate | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	187	205
Pension Benefits | Commingled Funds
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	1,964	2,289
Pension Benefits | Commingled Funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Commingled Funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Commingled Funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Commingled Funds | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	1,964	2,289
Pension Benefits | Short-Term Investments
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	117	173
Pension Benefits | Short-Term Investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	117	173
Pension Benefits | Short-Term Investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Short-Term Investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Short-Term Investments | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Other
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	(3)	52
Pension Benefits | Other | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	(3)	52
Pension Benefits | Other | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Other | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Pension Benefits | Other | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	2,094	2,111	$ 2,025
Other Benefits | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	366	242
Other Benefits | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	1,133	1,757
Other Benefits | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	39	35
Other Benefits | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	556	77
Other Benefits | Equity
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	283	104
Other Benefits | Equity | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	283	104
Other Benefits | Equity | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Equity | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Equity | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | U. S. companies
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	186	77
Other Benefits | U. S. companies | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	186	77
Other Benefits | U. S. companies | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | U. S. companies | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | U. S. companies | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | International companies
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	97	27
Other Benefits | International companies | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	97	27
Other Benefits | International companies | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | International companies | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | International companies | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	1,133	1,757
Other Benefits | Fixed Income | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Fixed Income | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	1,133	1,757
Other Benefits | Fixed Income | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Fixed Income | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Corporate Bonds - U.S.
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	718	1,121
Other Benefits | Corporate Bonds - U.S. | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Corporate Bonds - U.S. | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	718	1,121
Other Benefits | Corporate Bonds - U.S. | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Corporate Bonds - U.S. | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Corporate Bonds - Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	191	231
Other Benefits | Corporate Bonds - Non-U.S. | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Corporate Bonds - Non-U.S. | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	191	231
Other Benefits | Corporate Bonds - Non-U.S. | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Corporate Bonds - Non-U.S. | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | U.S. government and agencies
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	198	365
Other Benefits | U.S. government and agencies | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | U.S. government and agencies | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	198	365
Other Benefits | U.S. government and agencies | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | U.S. government and agencies | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Non-U.S. government
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	17	9
Other Benefits | Non-U.S. government | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Non-U.S. government | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	17	9
Other Benefits | Non-U.S. government | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Non-U.S. government | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Mortgage and asset-backed securities
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	9	31
Other Benefits | Mortgage and asset-backed securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Mortgage and asset-backed securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	9	31
Other Benefits | Mortgage and asset-backed securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Mortgage and asset-backed securities | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Alternatives
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	161	112
Other Benefits | Alternatives | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Alternatives | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Alternatives | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	39	35
Other Benefits | Alternatives | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	122	77
Other Benefits | Timberlands
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	35
Other Benefits | Timberlands | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Timberlands | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Timberlands | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	35
Other Benefits | Timberlands | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	35	0
Other Benefits | Other alternatives
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	41	0
Other Benefits | Other alternatives | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Other alternatives | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Other alternatives | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	39	0
Other Benefits | Other alternatives | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	2	0
Other Benefits | Private equity
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	59	48
Other Benefits | Private equity | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Private equity | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Private equity | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Private equity | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	59	48
Other Benefits | Real estate
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	26	29
Other Benefits | Real estate | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Real estate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Real estate | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Real estate | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	26	29
Other Benefits | Commingled Funds
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	434	0
Other Benefits | Commingled Funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Commingled Funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Commingled Funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Commingled Funds | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	434	0
Other Benefits | Short-Term Investments
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	71	102
Other Benefits | Short-Term Investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	71	102
Other Benefits | Short-Term Investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Short-Term Investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Short-Term Investments | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Other
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	12	36
Other Benefits | Other | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	12	36
Other Benefits | Other | Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Other | Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	0	0
Other Benefits | Other | Measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	$ 0	$ 0