Schedule II - Valuation and Qualifying Accounts (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at End of Period		$ 4
Allowance for Bad Debts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	72	65	61
Charged to Expense / Reduction in Revenue	(1)	39	20
Deductions	(6)	(32)	(16)
Balance at End of Period	65	72	65
Allowance for Sales Returns
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	86	133	158
Charged to Expense / Reduction in Revenue	55	17	19
Deductions	(65)	(64)	(44)
Balance at End of Period	76	86	133
Tax Valuation Allowance
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	183	151	126
Charged to Expense / Reduction in Revenue	32	33	25
Deductions	(4)	(1)	0
Balance at End of Period	$ 211	$ 183	$ 151