Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Indefinite-life intangible assets	$ 17,492	$ 17,296
Definite-life intangible assets	2,907	2,374
Total intangible assets, gross	20,399	19,670	$ 19,529
Accumulated amortization	(1,917)	(1,713)
Intangible assets, net	$ 18,482	$ 17,957