Acquisitions, Goodwill, and Acquired Intangible Assets - Summary of Goodwill Activity by Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Roll Forward]
Goodwill, balance at beginning of period	$ 14,754	$ 14,548
New acquisitions	212	189
Other adjustments	51	17
Goodwill, balance at end of period	15,017	14,754
North America
Goodwill [Roll Forward]
Goodwill, balance at beginning of period	12,264	12,191
New acquisitions	204	71
Other adjustments	59	2
Goodwill, balance at end of period	12,527	12,264
International
Goodwill [Roll Forward]
Goodwill, balance at beginning of period	1,300	1,270
New acquisitions	6	29
Other adjustments	(18)	1
Goodwill, balance at end of period	1,288	1,300
AWS
Goodwill [Roll Forward]
Goodwill, balance at beginning of period	1,190	1,087
New acquisitions	2	89
Other adjustments	10	14
Goodwill, balance at end of period	$ 1,202	$ 1,190