Goodwill and Other Intangible Assets - Schedule of other intangible assets by asset class (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 3,658	$ 4,013
Accumulated Amortization and Impairment	2,509	2,280
Net Carrying Amount	1,149	1,733
Customer related and contract based
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,240	2,550
Accumulated Amortization and Impairment	1,444	1,415
Net Carrying Amount	796	1,135
Tradenames
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,027	1,047
Accumulated Amortization and Impairment	740	533
Net Carrying Amount	287	514
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	391	416
Accumulated Amortization and Impairment	325	332
Net Carrying Amount	$ 66	$ 84