(Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ (4,739)	$ (4,500)
Balance at end of period	(4,342)	(4,739)	$ (4,500)
Defined Benefit Pension and Postretirement Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(2,277)	(1,916)	(2,527)
Other comprehensive income (loss) before reclassifications	227	2	22
Reclassification of stranded tax effects	0	(527)	0
Amounts reclassified from accumulated other comprehensive income	170	164	589
Balance at end of period	(1,880)	(2,277)	(1,916)
Change in Cumulative Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(2,465)	(2,581)	(2,111)
Other comprehensive income (loss) before reclassifications	(319)	14	(475)
Amounts reclassified from accumulated other comprehensive income	327	102	2
Other Comprehensive Income (Loss) Attributable to Noncontrolling Interest	0	0	3
Balance at end of period	(2,457)	(2,465)	(2,581)
Net Gains and Losses on Cash Flow Hedging Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	3	(3)	5
Other comprehensive income (loss) before reclassifications	(34)	4	(10)
Reclassification of stranded tax effects	0	(2)	0
Amounts reclassified from accumulated other comprehensive income	26	4	2
Balance at end of period	$ (5)	$ 3	$ (3)