Other Comprehensive Income Information (Amounts Reclassified Out Of Acc Other Comp Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Other Comprehensive Income Information Before Tax [Abstract]
Foreign exchange translation gain/(loss) included in net income (Statement of Income line: Other Income)	$ (14)	$ 0	$ (14)	$ 0
Amortization and settlement of postretirement benefits reserves adjustment included in net periodic benefit costs (Statement of Income line: Non-service pension and postretirement benefit expense)	$ (268)	$ (236)	$ (790)	$ (664)