CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Changes in unamortized net pension and other postretirement benefit gain (loss), tax expense (benefit)	$ 480	$ (191)	$ (243)
Changes in unamortized prior service credit (loss), tax expense (benefit)	$ 23	$ (51)	$ 49