Accumulated Other Comprehensive Loss (Details 2) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Reclassifications out of accumulated other comprehensive income loss by component
INCOME BEFORE INCOME TAX EXPENSE	$ 234	$ 323	$ 557	$ 654
Income tax expense	(91)	(130)	(222)	(258)
Net income	143	193	335	396
Amount reclassified from accumulated other comprehensive loss
Reclassifications out of accumulated other comprehensive income loss by component
Net actuarial loss	(42)	(5)	(80)	(10)
Prior service cost	(7)	(8)	(13)	(13)
INCOME BEFORE INCOME TAX EXPENSE	(49)	(13)	(93)	(23)
Income tax expense	18	5	35	9
Net income	$ (31)	$ (8)	$ (58)	$ (14)