Other Comprehensive Earnings (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended		3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Defined benefit plan Amount Reclassified from Accumulated Other Comprehensive Income (Loss)	Mar. 31, 2013 Defined benefit plan Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Reclassifications out of accumulated other comprehensive income (loss) by component
Net actuarial loss					$ (21)	$ (21)
Prior service cost					(1)	(1)
Total before tax	(394)	(123)	(899)	(454)	(22)	(22)
Income tax expense (benefit)	125	49	332	180	10	8
Insignificant items					(1)
Net of tax	$ (269)	$ (74)	$ (567)	$ (274)	$ (13)	$ (14)