Intangible Assets - Schedule of Intangible Assets by Class (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 3,919	$ 3,695
Accumulated Amortization	2,031	1,862
Net Book Value	1,888	1,833
Customer related intangible assets
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,253	2,200
Accumulated Amortization	1,136	1,043
Net Book Value	1,117	1,157
Acquired software and technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	587	507
Accumulated Amortization	452	432
Net Book Value	135	75
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	117	117
Accumulated Amortization	62	57
Net Book Value	55	60
Capitalized software development costs
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	714	641
Accumulated Amortization	272	233
Net Book Value	442	408
Purchased software
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	248	230
Accumulated Amortization	109	97
Net Book Value	$ 139	$ 133