Consolidated Statement of Comprehensive Income (Loss) Consolidated Statement of Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Pension and other postretirement benefit plan activity, tax expense (benefit)	$ 4	$ 3	$ 4	$ 3