Commitments and Contingencies Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Minimum lease obligations [Abstract]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	$ 107
Operating Leases, Future Minimum Payments, Due in Two Years	81
Operating Leases, Future Minimum Payments, Due in Three Years	74
Operating Leases, Future Minimum Payments, Due in Four Years	51
Operating Leases, Future Minimum Payments, Due in Five Years	39
Operating Leases, Rent Expense	$ 132	$ 148	$ 128