Goodwill and Other Intangible Assets - Schedule of other intangible assets by asset class (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 2,786	$ 3,673
Accumulated Amortization and Impairment	2,146	2,890
Net Carrying Amount	640	783
Amortization and impairment of intangible assets	246	392	$ 593
Customer-related and contract-based
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,337	2,264
Accumulated Amortization and Impairment	1,775	1,600
Net Carrying Amount	562	664
Trade Names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	14	1,029
Accumulated Amortization and Impairment	13	956
Net Carrying Amount	1	73
Impairment of intangible assets	1,000
Technology and other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	435	380
Accumulated Amortization and Impairment	358	334
Net Carrying Amount	$ 77	$ 46