Business Acquisitions, Goodwill, and Intangible Assets - Schedule of Intangible Assets (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 2,115	$ 2,136
Accumulated Amortization	(1,633)	(1,653)
Trademarks and other	7	7
Total	2,122	2,143
Purchased service portfolios
Finite-Lived Intangible Assets [Line Items]
Gross Amount	2,042	2,069
Accumulated Amortization	(1,575)	(1,598)
Patents, trademarks/trade names
Finite-Lived Intangible Assets [Line Items]
Gross Amount	21	21
Accumulated Amortization	(16)	(15)
Customer relationships and other
Finite-Lived Intangible Assets [Line Items]
Gross Amount	52	46
Accumulated Amortization	$ (42)	$ (40)