Goodwill, Customer Relationships and Other Intangible Assets - Schedule of Goodwill, Customer Relationships, and Other Intangible Assets (Details) - USD ($) $ in Millions	Jun. 30, 2021	Jan. 31, 2021	Dec. 31, 2020
Goodwill [Line Items]
Goodwill	$ 18,867	$ 0	$ 18,870
Indefinite-life intangible assets	9		278
Total other intangible assets, net	7,663		8,219
Customer relationships
Goodwill [Line Items]
Finite-lived intangible assets, net	5,856		6,344
Accumulated amortization	11,546		11,060
Capitalized software
Goodwill [Line Items]
Finite-lived intangible assets, net	1,481		1,520
Accumulated amortization	3,432		3,279
Trade names, patents and other
Goodwill [Line Items]
Finite-lived intangible assets, net	317		77
Accumulated amortization	$ 149		$ 120