Divestiture Transactions and Discontinued Operations Divestiture Transactions and Discontinued Operations (Components of Discontinued Operations in Consolidated Statement of Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Discontinued Operations and Disposal Groups [Abstract]
Operating revenues	$ 0	$ 0	$ 0	$ 1
Operating benefits (expenses)	0	(1)	3	(3)
Operating income (loss) before income tax	0	(1)	3	(2)
Income tax benefit	52	0	49	0
Income (loss) from discontinued operations, net of taxes	$ 52	$ (1)	$ 52	$ (2)