Equity, Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Changes in Accumulated Other Comprehensive Income (Loss), By Component
Beginning balance, accumulated other comprehensive income (loss), net of tax	$ 20,527
Ending balance, accumulated other comprehensive income (loss), net of tax	20,656
Accumulated Other Comprehensive Income (Loss) [Member]
Changes in Accumulated Other Comprehensive Income (Loss), By Component
Beginning balance, accumulated other comprehensive income (loss), net of tax	(933)	$ (367)
Other comprehensive income (loss) before reclassifications	129	(366)
Amounts reclassified from accumulated other comprehensive loss	2	3
Net other comprehensive income (loss)	131	(363)
Ending balance, accumulated other comprehensive income (loss), net of tax	(802)	(730)
Foreign Currency Translation Adjustment [Member]
Changes in Accumulated Other Comprehensive Income (Loss), By Component
Beginning balance, accumulated other comprehensive income (loss), net of tax	(605)	1
Other comprehensive income (loss) before reclassifications	121	(366)
Amounts reclassified from accumulated other comprehensive loss	0	0
Net other comprehensive income (loss)	121	(366)
Ending balance, accumulated other comprehensive income (loss), net of tax	(484)	(365)
Defined Benefit Plans Items [Member]
Changes in Accumulated Other Comprehensive Income (Loss), By Component
Beginning balance, accumulated other comprehensive income (loss), net of tax	(328)	(368)
Other comprehensive income (loss) before reclassifications	8	0
Amounts reclassified from accumulated other comprehensive loss	2	3
Net other comprehensive income (loss)	10	3
Ending balance, accumulated other comprehensive income (loss), net of tax	$ (318)	$ (365)