Guarantees (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Maximum potential amount of undiscounted future payments [Member]
Type of Guarantee
Return and Merchant Protection	$ 42,000	$ 37,000
Other	6,000	8,000
Total	48,000	45,000
Amount of related liability [Member]
Type of Guarantee
Return and Merchant Protection	49	44
Other	57	67
Total	$ 106	$ 111