Reclassifications out of Accumulated Other Comprehensive Income Reclassifications out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Provision for income taxes	$ 276	$ 144
Other insignificant, net of tax	(109)	(107)
Total reclassifications	(407)	(276)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of actuarial loss	(3)	(7)
Net settlement loss	(48)	(17)
Net curtailment gain (loss)	0	5
Income before income taxes	(51)	(19)
Provision for income taxes	19	7
Total reclassifications	$ (32)	$ (12)