Summary of Significant Accounting Policies - Schedule of Intangible Assets by Class (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 3,594	$ 3,576
Accumulated Amortization	1,722	1,573
Net Book Value	1,872	2,003
Customer related intangible assets
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,155	2,155
Accumulated Amortization	922	797
Net Book Value	1,233	1,358
Acquired software and technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	488	493
Accumulated Amortization	413	356
Net Book Value	75	137
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	120	120
Accumulated Amortization	53	46
Net Book Value	67	74
Capitalized software development costs
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	575	574
Accumulated Amortization	199	240
Net Book Value	376	334
Purchased software
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	256	234
Accumulated Amortization	135	134
Net Book Value	$ 121	$ 100