Income Taxes (Net Deferred Income Tax Assets and Liabilities) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Examination [Line Items]
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount	$ 172	$ 167
Employee benefits	386	439
Contingent and accrued liabilities	74	118
Operating loss and other carry-forwards	278	293
Operating lease liabilities	215	209
Other	121	197
Deferred Tax Assets, Valuation Allowance	172	167
Deferred Tax Assets, Net of Valuation Allowance	970	1,089
Property	278	240
Intangibles	814	663
Employee benefits	75	37
Operating lease right-of-use assets	216	206
Other	36	16
Deferred Tax Liabilities, Gross	1,419	1,162
Deferred Tax Liabilities, Net	449	73
Income Tax, Potential U.S. Tax Cost for Repatriation of Foreign Earnings	39	40
Deferred income tax assets related to
Employee benefits	386	439
Contingent and accrued liabilities	74	118
Operating loss and other carry-forwards	278	293
Operating lease liabilities	215	209
Research and development amortization	68	0
Other	121	197
Valuation allowance	(172)	(167)
Total	970	1,089
Deferred income tax liabilities related to
Property	278	240
Intangibles	814	663
Employee benefits	75	37
Operating lease right-of-use assets	216	206
Other	36	16
Total	1,419	1,162
Deferred income tax liabilities – net	$ (449)	$ (73)
Minimum
Income Tax Examination [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2022
Tax Credit Carryforward, Expiration Date	Dec. 31, 2022
Maximum
Income Tax Examination [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2041
Tax Credit Carryforward, Expiration Date	Dec. 31, 2041