Schedule II - Valuation Accounts and Reserves (Details) - Valuation Accounts and Reserves - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance for Doubtful Accounts [Member]
Valuation Allowance [Line Items]
Balance at beginning of period	$ 47	$ 28	$ 26
Additions	1	19	2
Balance at end of period	48	47	28
Valuation Allowance of Deferred Tax Assets [Member]
Valuation Allowance [Line Items]
Balance at beginning of period	298	286	210
Additions	30	186	80
Net deductions and other	90	174	4
Balance at end of period	238	298	286
Accumulated Amortization of Purchased Intangible Assets [Member]
Valuation Allowance [Line Items]
Balance at beginning of period	216	185	154
Additions	49	31	31
Balance at end of period	265	216	185
Business Restructuring Reserves [Member]
Valuation Allowance [Line Items]
Balance at beginning of period	44	44	42
Additions		49	41
Net deductions and other	41	49	39
Balance at end of period	$ 3	$ 44	$ 44