Land, Buildings, Equipment and Software, Net - Depreciation Expense, Operating Lease Rent Expense, Minimum Operating Lease Commitments (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Depreciation expense	[1]	$ 277	$ 324	$ 332
Operating lease rent expense		553	560	$ 513
Capital Leased Assets, Gross		98	$ 105
Continuing Operations [Member]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2016		378
2017		271
2018		178
2019		122
2020		78
Thereafter		$ 139

[1] Excludes amounts related to our ITO business, which was reported as a discontinued operation through its date of sale on June 30, 2015. Refer to Note 4 - Divestitures for additional information regarding this sale.