Intangible Assets Including Goodwill - Intangible Assets by Class (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Intangible asset balances by major asset class:
Gross Carrying Amount	$ 8,314	$ 8,466
Accumulated Amortization	(3,879)	(3,778)
Net Carrying Amount	4,436	4,688
Capitalized software
Intangible asset balances by major asset class:
Gross Carrying Amount	1,557	1,537
Accumulated Amortization	(691)	(661)
Net Carrying Amount	865	876
Client relationships
Intangible asset balances by major asset class:
Gross Carrying Amount	2,751	2,831
Accumulated Amortization	(1,254)	(1,228)
Net Carrying Amount	1,497	1,602
Completed technology
Intangible asset balances by major asset class:
Gross Carrying Amount	3,231	3,322
Accumulated Amortization	(1,688)	(1,668)
Net Carrying Amount	1,542	1,654
Patents/trademarks
Intangible asset balances by major asset class:
Gross Carrying Amount	725	730
Accumulated Amortization	(228)	(205)
Net Carrying Amount	496	525
Other intangible assets
Intangible asset balances by major asset class:
Gross Carrying Amount	52	46
Accumulated Amortization	(17)	(15)
Net Carrying Amount	$ 35	$ 31