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		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Discontinued Operations and Disposal Groups [Abstract]
Operating revenues	$ 0	$ 0	$ 0	$ 1
Operating benefits (expenses)	(1)	(1)	2	(4)
Operating income (loss) before income tax	(1)	(1)	2	(3)
Income tax benefit	1	0	50	0
Income (loss) from discontinued operations, net of taxes	$ 0	$ (1)	$ 52	$ (3)