Reclassifications out of Accumulated Other Comprehensive Loss Changes in Accumulated Other Comprehensive Loss by Component (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Changes in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	$ (3,947)	$ (4,560)
Other comprehensive income (loss) before reclassifications	(5)	76
Amounts reclassified from accumulated other comprehensive loss	70	60
Purchase of subsidiary shares from minority interest	(1)
Balance at end of period	(3,883)	(4,424)
Foreign Currency Translation Adjustment
Changes in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	(690)	(538)
Other comprehensive income (loss) before reclassifications	(6)	(40)
Amounts reclassified from accumulated other comprehensive loss	0	1
Purchase of subsidiary shares from minority interest	(1)
Balance at end of period	(697)	(577)
Unrecognized Net Actuarial Losses and Prior Service Costs
Changes in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	(3,290)	(4,044)
Other comprehensive income (loss) before reclassifications	8	96
Amounts reclassified from accumulated other comprehensive loss	69	59
Purchase of subsidiary shares from minority interest	0
Balance at end of period	(3,213)	(3,889)
Deferred Derivative Gains (Losses)
Changes in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	(1)	(4)
Other comprehensive income (loss) before reclassifications	(2)	3
Amounts reclassified from accumulated other comprehensive loss	1	0
Purchase of subsidiary shares from minority interest	0
Balance at end of period	(2)	(1)
Unrealized Investment Gains
Changes in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	34	26
Other comprehensive income (loss) before reclassifications	(5)	17
Amounts reclassified from accumulated other comprehensive loss	0	0
Purchase of subsidiary shares from minority interest	0
Balance at end of period	$ 29	$ 43