Reclassifications out of Accumulated Other Comprehensive Loss Changes in Accumulated Other Comprehensive Loss by Component (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Changes in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period			$ (4,143)	$ (3,947)
Other comprehensive income (loss) before reclassifications			(27)	27
Amounts reclassified from accumulated other comprehensive loss			27	91
Purchase of subsidiary shares from minority interest				(1)
Balance at end of period	$ (4,143)	$ (3,830)	(4,143)	(3,830)
Foreign Currency Translation Adjustment
Changes in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period			(894)	(690)
Other comprehensive income (loss) before reclassifications			(59)	15
Amounts reclassified from accumulated other comprehensive loss			1	(2)
Purchase of subsidiary shares from minority interest				(1)
Balance at end of period	(952)	(678)	(952)	(678)
Unrecognized Net Actuarial Losses and Prior Service Costs
Changes in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period			(3,297)	(3,290)
Other comprehensive income (loss) before reclassifications			22	12
Amounts reclassified from accumulated other comprehensive loss			37	93
Purchase of subsidiary shares from minority interest				0
Balance at end of period	(3,238)	(3,185)	(3,238)	(3,185)
Deferred Derivative Gains (Losses)
Changes in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period			12	(1)
Other comprehensive income (loss) before reclassifications			9	(1)
Amounts reclassified from accumulated other comprehensive loss			(11)	0
Purchase of subsidiary shares from minority interest				0
Balance at end of period	10	(2)	10	(2)
Unrealized Investment Gains
Changes in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period			36	34
Other comprehensive income (loss) before reclassifications			1	1
Amounts reclassified from accumulated other comprehensive loss			0	0
Purchase of subsidiary shares from minority interest				0
Balance at end of period	37	35	37	35
Reclassification Out of Accumulated Other Comprehensive Income | Unrecognized Net Actuarial Losses and Prior Service Costs
Changes in Accumulated Other Comprehensive Loss by Component [Line Items]
Total Benefit Cost	$ 29	$ 26	$ 57	$ 102