Goodwill, Customer Relationships and Other Intangible Assets - Schedule of Goodwill and Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived and Indefinite-Lived Intangible Assets
Goodwill	$ 7,405	$ 7,415	$ 11,119
Finite lived intangible assets, net	6,605	7,334
Customer relationships
Finite-Lived and Indefinite-Lived Intangible Assets
Finite lived intangible assets, net	6,156	6,865
Accumulated amortization	2,246	1,538
Capitalized software
Finite-Lived and Indefinite-Lived Intangible Assets
Finite lived intangible assets, net	401	395
Accumulated amortization	256	146
Trade names
Finite-Lived and Indefinite-Lived Intangible Assets
Finite lived intangible assets, net	48	74
Accumulated amortization	$ 83	$ 57