Other Comprehensive Income (Loss) (Schedule of Components of Accumulated Other Comprehensive Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of January 1, 2013			$ (3,307)
Other comprehensive income (loss) before reclassifications			(49)
Amounts reclassified from accumulated other comprehensive income			143
Other comprehensive income, net of tax	222	110	94	183
Balance as of September 30, 2013	(3,213)		(3,213)
Unrealized Investment Gains [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of January 1, 2013			4
Other comprehensive income (loss) before reclassifications			(1)
Amounts reclassified from accumulated other comprehensive income			0
Other comprehensive income, net of tax			(1)
Balance as of September 30, 2013	3		3
Pension/Postretirement Plans Gains (Losses) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of January 1, 2013			(3,451)
Other comprehensive income (loss) before reclassifications			36
Amounts reclassified from accumulated other comprehensive income			143
Other comprehensive income, net of tax			179
Balance as of September 30, 2013	(3,272)		(3,272)
Foreign Currency Translation Adjustments [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of January 1, 2013			140
Other comprehensive income (loss) before reclassifications			(84)
Amounts reclassified from accumulated other comprehensive income			0
Other comprehensive income, net of tax			(84)
Balance as of September 30, 2013	$ 56		$ 56