Additional Information Schedule of Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance For Discounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$ 0	$ 0	$ 0
Charged to costs and expenses	618	599	610
Deductions	(618)	(599)	(610)
Balance at end of year	0	0	0
Allowance For Returned Goods [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	46	41	42
Charged to costs and expenses	217	179	150
Deductions	(195)	(174)	(151)
Balance at end of year	$ 68	$ 46	$ 41