Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Provision for income taxes	$ (905)	$ 754	$ (392)
Other insignificant items	(511)	(438)	(462)
Net Income (Loss) Attributable to Parent	2,140	2,204	$ (3,046)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Amortization of actuarial loss	(14)	(24)
Net settlement loss	(103)	(119)
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	0	8
Derivative Instruments, Income Statement Location of Gain (Loss) Reclassified from Accumulated OCI	4	0
Income from operations before income taxes	(113)	(135)
Provision for income taxes	41	51
Net Income (Loss) Attributable to Parent	$ 72	$ 84