Accumulated Other Comprehensive Loss (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Reclassifications out of accumulated other comprehensive income loss by component
INCOME BEFORE INCOME TAX EXPENSE	$ 323	$ 331
Income tax expense	(131)	(128)
Net income	192	203
Amount reclassified from accumulated other comprehensive loss
Reclassifications out of accumulated other comprehensive income loss by component
Net actuarial loss	(38)	(5)
Prior service cost	(6)	(5)
INCOME BEFORE INCOME TAX EXPENSE	(44)	(10)
Income tax expense	17	4
Net income	$ (27)	$ (6)