Regulatory Matters, Commitments, Contingencies And Environmental Liabilities Operating Leases, Rental Expense (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Rental expense(1)	[1]	$ 21	$ 54	$ 39	$ 106
Less: Sublease rental income		0	(4)	0	(12)
Rental expense, net		$ 21	$ 50	$ 39	$ 94

[1] (1) Includes contingent rentals totaling $6 million and $10 million for the three and six months ended June 30, 2015