Other Comprehensive Income (Loss) (Schedule of Components of Accumulated Other Comprehensive Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	$ (2,708)	$ (3,379)	$ (2,621)	$ (3,307)
Other comprehensive income (loss) before reclassifications	68	(103)	(53)	(220)
Amounts reclassified from accumulated other comprehensive income	33	47	67	92
Other comprehensive income (loss), net of tax	101	(56)	14	(128)
Balance, end of period	(2,607)	(3,435)	(2,607)	(3,435)
Unrealized Investment Gains [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	5	4	5	4
Other comprehensive income (loss) before reclassifications	0	(1)	0	(1)
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Other comprehensive income (loss), net of tax	0	(1)	0	(1)
Balance, end of period	5	3	5	3
Pension/Postretirement Plans Gains (Losses) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	(2,847)	(3,267)	(2,682)	(3,451)
Other comprehensive income (loss) before reclassifications	(69)	(18)	(268)	121
Amounts reclassified from accumulated other comprehensive income	33	47	67	92
Other comprehensive income (loss), net of tax	(36)	29	(201)	213
Balance, end of period	(2,883)	(3,238)	(2,883)	(3,238)
Foreign Currency Translation Adjustments [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	134	(116)	56	140
Other comprehensive income (loss) before reclassifications	137	(84)	215	(340)
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Other comprehensive income (loss), net of tax	137	(84)	215	(340)
Balance, end of period	$ 271	$ (200)	$ 271	$ (200)