Equity, Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Changes in Accumulated Other Comprehensive Income (Loss) by Component, Net of Tax
Beginning balance, accumulated other comprehensive income (loss), net of tax	$ 20,677
Separation of retail business			$ (479)
Ending balance, accumulated other comprehensive income (loss), net of tax	20,527	$ 20,677
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	(367)	350	108
Other comprehensive income (loss) before reclassifications	(585)	(717)	383
Amounts reclassified from accumulated other comprehensive income (loss)	19	0	18
Other comprehensive income (loss)	(566)	(717)	401
Separation of retail business			(159)
Ending balance, accumulated other comprehensive income (loss), net of tax	(933)	(367)	350
Accumulated 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	1	408	665
Other comprehensive income (loss) before reclassifications	(606)	(407)	(98)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0	0
Other comprehensive income (loss)	(606)	(407)	(98)
Separation of retail business			(159)
Ending balance, accumulated other comprehensive income (loss), net of tax	(605)	1	408
Accumulated Defined Benefit Plans Adjustment [Member]
Changes in Accumulated Other Comprehensive Income (Loss) by Component, Net of Tax
Beginning balance, accumulated other comprehensive income (loss), net of tax	(368)	(58)	(558)
Other comprehensive income (loss) before reclassifications	21	(309)	483
Amounts reclassified from accumulated other comprehensive income (loss)	19	(1)	17
Other comprehensive income (loss)	40	(310)	500
Separation of retail business			0
Ending balance, accumulated other comprehensive income (loss), net of tax	(328)	(368)	(58)
Accumulated Net Gain (Loss) from Designated or Qualifying 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	1
Other comprehensive income (loss) before reclassifications	0	(1)	(2)
Amounts reclassified from accumulated other comprehensive income (loss)	0	1	1
Other comprehensive income (loss)	0	0	(1)
Separation of retail business			0
Ending balance, accumulated other comprehensive income (loss), net of tax	$ 0	$ 0	$ 0