Income Taxes (Unrecognized Income Tax Benefits) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Expense (Benefit) [Abstract]
Balance at January 1	$ 435	$ 558	$ 568
Gross increases for tax positions of prior years	73	30	17
Gross decreases for tax positions of prior years	(31)	(104)	(60)
Gross increases for tax positions of the current year	37	52	55
Settlements	(35)	(100)	(15)
Unrecognized Tax Benefits, Other	6	1	7
Balance at December 31	$ 473	$ 435	$ 558