Other Comprehensive Income (Loss) (Schedule of Components of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period			$ 7,943
Other comprehensive income before reclassifications	$ 234	$ 44	(587)	$ 79
Amounts reclassified from accumulated other comprehensive income	31	19	60	41
Other comprehensive income (loss), net of tax	265	63	(527)	120
Balance, end of period	8,392	8,337	8,392	8,337
AOCI Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(5,847)	(4,590)	(5,055)	(4,647)
Other comprehensive income (loss), net of tax	265	63	(527)	120
Balance, end of period	(5,582)	(4,527)	(5,582)	(4,527)
Pension/Post-Retirement Plans Gains (Losses)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(3,374)	(2,990)	(3,512)	(2,953)
Other comprehensive income before reclassifications	(3)	29	106	(30)
Amounts reclassified from accumulated other comprehensive income	31	19	60	41
Other comprehensive income (loss), net of tax	28	48	166	11
Balance, end of period	(3,346)	(2,942)	(3,346)	(2,942)
Foreign Currency Translation Gains (Losses)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(2,473)	(1,600)	(1,543)	(1,694)
Other comprehensive income before reclassifications	237	15	(693)	109
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Other comprehensive income (loss), net of tax	237	15	(693)	109
Balance, end of period	$ (2,236)	$ (1,585)	$ (2,236)	$ (1,585)