Long-Term Debt (Credit Facility End of Period Disclosures Narrative) (Details) (USD $)			3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Credit Facility, Name [Member] Credit Facility, Type of Debt [Member] item	Mar. 31, 2014 Credit Facility, Revolving Credit Loans [Member] Line of Credit [Member]
Debt Instrument [Line Items]
Debt	$ 16,998,000,000	$ 9,453,000,000
Line of Credit Facility, Remaining Borrowing Capacity				1,000,000,000
Letters of Credit Outstanding, Amount				77,000,000
Minimum Number of Additional Tranches Available in Future			1
Aggregate Principal Amount of Each Tranche Available in Future			$ 1,500,000,000
Debt, Weighted Average Interest Rate			4.30%