Goodwill, Customer Relationships and Other Intangible Assets - Schedule of Goodwill and Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Oct. 31, 2017
Finite-Lived and Indefinite-Lived Intangible Assets
Goodwill	$ 11,119	$ 10,837	$ 10,821
Finite-lived intangible assets, net	7,567	8,845
Total other intangible assets, net	410	378
Customer relationships
Finite-Lived and Indefinite-Lived Intangible Assets
Finite-lived intangible assets, net	7,567	8,845
Accumulated amortization	883	126
Trade names
Finite-Lived and Indefinite-Lived Intangible Assets
Finite-lived intangible assets, net	100	126
Accumulated amortization	30	4
Developed technology
Finite-Lived and Indefinite-Lived Intangible Assets
Finite-lived intangible assets, net	310	252
Accumulated amortization	$ 67	$ 9