Long-Term Debt (Narrative) (Details) (USD $)	12 Months Ended								3 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Senior Notes [Member] Change Of Control And Loss Of Investment Grade Rating [Member]	Oct. 31, 2013 4% Note [Member] Senior Notes [Member]	Oct. 31, 2013 5.375% Note [Member] Senior Notes [Member]	May 02, 2013 2.95% Note [Member] Senior Notes [Member]	May 02, 2013 4.50% Note [Member] Senior Notes [Member]	Dec. 31, 2013 Senior Notes [Member]	Sep. 30, 2012 Senior Notes [Member]	Dec. 31, 2013 Senior Notes [Member]	Dec. 31, 2012 Senior Notes [Member]	Dec. 31, 2013 Subject to Credit Rating Step Up [Member] Notes Issued, 2008 and 2009 [Member] Senior Notes [Member]
Debt Instrument [Line Items]
Aggregate principal amount					$ 1,400,000,000	$ 1,800,000,000	$ 350,000,000	$ 650,000,000					$ 4,725,000,000
Stated interest rate					4.00%	5.375%	2.95%	4.50%
Required purchase price as percentage of aggregate principal amount				101.00%
Long-term debt repaid	3,559,000,000	2,600,000,000	0						1,459,000,000
Extinguishment of Debt, Amount									$ 2,100,000,000	$ 2,000,000,000	$ 2,100,000,000	$ 2,000,000,000