Goodwill, Customer Relationships and Other Intangible Assets - Schedule of Goodwill, Customer Relationships, and Other Intangible Assets (Details) - USD ($) $ in Millions	Mar. 31, 2021	Jan. 31, 2021	Dec. 31, 2020
Goodwill [Line Items]
Goodwill	$ 18,854	$ 0	$ 18,870
Indefinite-life intangible assets	9		278
Total other intangible assets, net	7,884		8,219
Customer relationships
Goodwill [Line Items]
Finite-lived intangible assets, net	6,035		6,344
Accumulated amortization	11,356		11,060
Capitalized software
Goodwill [Line Items]
Finite-lived intangible assets, net	1,509		1,520
Accumulated amortization	3,366		3,279
Trade names, patents and other
Goodwill [Line Items]
Finite-lived intangible assets, net	331		77
Accumulated amortization	$ 134		$ 120