Accumulated Other Comprehensive Loss (Details 2) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
INCOME BEFORE INCOME TAX EXPENSE									$ (1,316)	$ (1,110)	$ (224)
Income tax expense									(438)	(338)	(463)
Other income, net									23	11	59
NET INCOME (LOSS)	$ 338	$ 205	$ 143	$ 192	$ 188	$ 188	$ 193	$ 203	878	772	$ (239)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net actuarial loss									161	(85)
Prior service cost									24	(25)
INCOME BEFORE INCOME TAX EXPENSE									(185)	110
Income tax expense									(70)	42
Other income, net										1
NET INCOME (LOSS)									$ 115	$ 69