CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Tax benefit of actuarial losses	$ 15	$ 10	$ 64	$ 31
Tax expense of prior service credits	$ 0	$ 0	$ (3)	$ (49)