Accumulated Other Comprehensive Loss (Details 2) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Reclassifications out of accumulated other comprehensive income loss by component
INCOME BEFORE INCOME TAX EXPENSE	$ 329	$ 299	$ 886	$ 953
Income tax expense	(124)	(111)	(346)	(369)
Net income	205	188	540	584
Amount reclassified from accumulated other comprehensive loss
Reclassifications out of accumulated other comprehensive income loss by component
Net actuarial loss	(40)	(5)	(120)	(15)
Prior service cost	(7)	(5)	(20)	(18)
INCOME BEFORE INCOME TAX EXPENSE	(47)	(10)	(140)	(33)
Income tax expense	19	4	54	13
Net income	$ (28)	$ (6)	$ (86)	$ (20)