Other Comprehensive Income (Loss) (Schedule of Components of Accumulated Other Comprehensive Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	$ (2,621)	$ (3,307)
Other comprehensive income (loss) before reclassifications	(121)	(117)
Amounts reclassified from accumulated other comprehensive income	34	45
Other comprehensive loss, net of tax	(87)	(72)
Balance, end of period	(2,708)	(3,379)
Unrealized Investment Gains [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	5	4
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income	0	0
Other comprehensive loss, net of tax	0	0
Balance, end of period	5	4
Pension/Postretirement Plans Gains (Losses) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	(2,682)	(3,451)
Other comprehensive income (loss) before reclassifications	(199)	139
Amounts reclassified from accumulated other comprehensive income	34	45
Other comprehensive loss, net of tax	(165)	184
Balance, end of period	(2,847)	(3,267)
Foreign Currency Translation Adjustments [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	56	140
Other comprehensive income (loss) before reclassifications	78	(256)
Amounts reclassified from accumulated other comprehensive income	0	0
Other comprehensive loss, net of tax	78	(256)
Balance, end of period	$ 134	$ (116)