Goodwill, Customer Relationships and Other Intangible Assets - Schedule of Goodwill and Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived and Indefinite-Lived Intangible Assets
Goodwill	$ 7,415	$ 11,119	$ 10,837
Finite lived intangible assets, net		7,567
Customer relationships
Finite-Lived and Indefinite-Lived Intangible Assets
Finite lived intangible assets, net	6,865	7,567
Accumulated amortization	1,538	833
Other intangible assets
Finite-Lived and Indefinite-Lived Intangible Assets
Finite lived intangible assets, net	469	410
Trade names
Finite-Lived and Indefinite-Lived Intangible Assets
Finite lived intangible assets, net	74	100
Accumulated amortization	57	30
Capitalized software
Finite-Lived and Indefinite-Lived Intangible Assets
Finite lived intangible assets, net	395	310
Accumulated amortization	$ 146	$ 67