Equity (Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax, Beginning Balance	$ (3,256)	$ (2,595)
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax, Beginning Balance	(353)	(396)
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax, Beginning Balance	(274)	(295)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	(3,883)	(3,286)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	106	(660)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	1,021	50
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	1,181	(1,019)	$ (494)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	42	9	(259)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	(187)	77	(20)
Other Comprehensive Income (Loss), Net of Tax	1,036	(933)	(773)
Cumulative Effect of New Accounting Principle in Period of Adoption		13
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax, Ending Balance	(2,147)	(3,256)	(2,595)
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax, Ending Balance	(323)	(353)	(396)
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax, Ending Balance	(286)	(274)	(295)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	(2,756)	(3,883)	(3,286)
Available-for-Sale securities, net
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	117	(674)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	992	0
Cumulative Effect of New Accounting Principle in Period of Adoption		13
Unrealized derivative gains (losses), net
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	2	(5)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	28	48
Cumulative Effect of New Accounting Principle in Period of Adoption		0
Unfunded pension obligations, net
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(13)	19
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	1	2
Cumulative Effect of New Accounting Principle in Period of Adoption		0
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	1,109	(674)	(332)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	30	43	(108)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	(12)	21	(4)
Other Comprehensive Income (Loss), Net of Tax	$ 1,127	$ (610)	$ (444)