Components of Accumulated Other Comprehensive Loss, Net (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 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	34	$ (32)
Other comprehensive income (loss), foreign currency translation adjustment	(548)	155
Other comprehensive income (loss), unrealized gains (losses) on cash flow hedges	(33)	(8)
Other comprehensive income (loss)	(547)	115
Ending balance - Accumulated other comprehensive loss, net	(2,253)
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	34	(32)
Other comprehensive income (loss), foreign currency translation adjustment	(548)	155
Other comprehensive income (loss), unrealized gains (losses) on cash flow hedges	(33)	(8)
Other comprehensive income (loss)	(547)	115
Ending balance - unrecognized amounts on retirement benefits	(383)	(390)
Ending balance - foreign currency translation adjustment	(1,844)	(1,468)
Ending balance - unrealized gains (losses) on cash flow hedges	(26)	28
Ending balance - Accumulated other comprehensive loss, net	$ (2,253)	$ (1,830)