CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Tax benefit of actuarial losses	$ (26)	$ (8)	$ (49)	$ (21)
Tax expense of prior service credits	$ 3	$ 19	$ 3	$ 49