Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 15,037	$ 12,805
Other comprehensive income (loss) before reclassifications	12	2
Amounts reclassified from accumulated other comprehensive income (loss) into earnings	10	(11)
Ending balance	15,331	13,021
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(589)	(624)
Other comprehensive income (loss) before reclassifications	(5)	(12)
Amounts reclassified from accumulated other comprehensive income (loss) into earnings	0	(2)
Ending balance	(594)	(638)
Unrealized gain (loss) on forward contracts
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(28)	8
Other comprehensive income (loss) before reclassifications	20	10
Amounts reclassified from accumulated other comprehensive income (loss) into earnings	9	(9)
Ending balance	1	9
Unrealized gain (loss) on available-for-sale securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(5)	(3)
Other comprehensive income (loss) before reclassifications	(3)	4
Amounts reclassified from accumulated other comprehensive income (loss) into earnings	1	0
Ending balance	(7)	1
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(622)	(619)
Ending balance	$ (600)	$ (628)