Reclassifications out of Accumulated Other Comprehensive Income Reclassifications out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Provision for income taxes	$ 68	$ 6	$ 344	$ 150
Other insignificant, net of tax	(95)	(81)	(204)	(188)
Total reclassifications	(170)	(386)	(577)	(662)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of actuarial loss	(4)	(7)	(7)	(14)
Net settlement loss	(31)	(64)	(79)	(81)
Net curtailment gain (loss)	0	(2)	0	3
Income before income taxes	(35)	(73)	(86)	(92)
Provision for income taxes	13	25	29	32
Total reclassifications	$ (22)	$ (48)	$ (57)	$ (60)