Pension and Other Postretirement Benefits (Amounts Recognized in Consolidated Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Noncurrent liabilities	$ (1,015)	$ (2,121)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Current liabilities	(11)	(9)
Noncurrent liabilities	(241)	(1,041)
Accrued benefit cost	(252)	(1,050)
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Current liabilities	(54)	(51)
Noncurrent liabilities	(774)	(1,080)
Accrued benefit cost	$ (828)	$ (1,131)