Components of Accumulated Other Comprehensive Loss, Net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance - Accumulated other comprehensive loss, net			$ (1,706)
Other comprehensive income (loss), unrecognized amounts on retirement benefits	$ (6)	$ (26)	38	$ (40)
Other comprehensive income (loss), foreign currency translation adjustment	244	(172)	(195)	(66)
Other comprehensive income (loss), unrealized gains (losses) on cash flow hedges	4	7	(20)	(28)
Other comprehensive income (loss)	242	(191)	(177)	(134)
Ending balance - Accumulated other comprehensive loss, net	(1,883)		(1,883)
Accumulated Other Comprehensive (Loss) Income, Net [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance - unrecognized amounts on retirement benefits			(417)	(358)
Beginning balance - foreign currency translation adjustment			(1,296)	(1,623)
Beginning balance - unrealized gains (losses) on cash flow hedges			7	36
Beginning balance - Accumulated other comprehensive loss, net			(1,706)	(1,945)
Other comprehensive income (loss), unrecognized amounts on retirement benefits			38	(40)
Other comprehensive income (loss), foreign currency translation adjustment			(195)	(66)
Other comprehensive income (loss), unrealized gains (losses) on cash flow hedges			(20)	(28)
Other comprehensive income (loss)	242	(191)	(177)	(134)
Ending balance - unrecognized amounts on retirement benefits	(379)	(398)	(379)	(398)
Ending balance - foreign currency translation adjustment	(1,491)	(1,689)	(1,491)	(1,689)
Ending balance - unrealized gains (losses) on cash flow hedges	(13)	8	(13)	8
Ending balance - Accumulated other comprehensive loss, net	$ (1,883)	$ (2,079)	$ (1,883)	$ (2,079)