Equity, Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Changes in Accumulated Other Comprehensive Income (Loss) by Component, Net of Tax
Beginning balance, accumulated other comprehensive income (loss), net of tax	$ 20,527
Ending balance, accumulated other comprehensive income (loss), net of tax	20,024	$ 20,527
Accumulated Other Comprehensive Income (Loss) [Member]
Changes in Accumulated Other Comprehensive Income (Loss) by Component, Net of Tax
Beginning balance, accumulated other comprehensive income (loss), net of tax	(933)	(367)	$ 350
Other comprehensive income (loss) before reclassifications	(484)	(585)	(717)
Amounts reclassified from accumulated other comprehensive income (loss)	7	19	0
Net other comprehensive income (loss)	(477)	(566)	(717)
Ending balance, accumulated other comprehensive income (loss), net of tax	(1,410)	(933)	(367)
Accumulated Foreign Currency Translation Adjustment [Member]
Changes in Accumulated Other Comprehensive Income (Loss) by Component, Net of Tax
Beginning balance, accumulated other comprehensive income (loss), net of tax	(605)	1	408
Other comprehensive income (loss) before reclassifications	(416)	(606)	(407)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0	0
Net other comprehensive income (loss)	(416)	(606)	(407)
Ending balance, accumulated other comprehensive income (loss), net of tax	(1,021)	(605)	1
Accumulated Defined Benefit Plan Items Adjustment [Member]
Changes in Accumulated Other Comprehensive Income (Loss) by Component, Net of Tax
Beginning balance, accumulated other comprehensive income (loss), net of tax	(328)	(368)	(58)
Other comprehensive income (loss) before reclassifications	(68)	21	(309)
Amounts reclassified from accumulated other comprehensive income (loss)	7	19	(1)
Net other comprehensive income (loss)	(61)	40	(310)
Ending balance, accumulated other comprehensive income (loss), net of tax	(389)	(328)	(368)
Accumulated Gains and (Losses) on Cash Flow Hedges [Member]
Changes in Accumulated Other Comprehensive Income (Loss) by Component, Net of Tax
Beginning balance, accumulated other comprehensive income (loss), net of tax	0	0	0
Other comprehensive income (loss) before reclassifications	0	0	(1)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0	1
Net other comprehensive income (loss)	0	0	0
Ending balance, accumulated other comprehensive income (loss), net of tax	$ 0	$ 0	$ 0