Contingencies (Nu Mark Patent Litigation) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended			6 Months Ended
	Jan. 31, 2017	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Jun. 30, 2017
Loss Contingencies [Line Items]
Litigation settlement, amount		$ 1,200		$ 1,200	$ 2,300
Nu Mark Patent Litigation [Member]
Loss Contingencies [Line Items]
Proceeds from legal settlements	$ 21
Litigation settlement, amount			$ 21