Debt And Financing Activities (Senior Bridge Term Loan Facility) (Narrative) (Details) (USD $)	1 Months Ended	12 Months Ended
	Jan. 31, 2014	Mar. 31, 2014	Mar. 31, 2013	Feb. 28, 2013	Dec. 31, 2012
Senior Bridge Term Loan Agreement, 2014 [Member]
Debt Instrument [Line Items]
Credit facility borrowing capacity	$ 5,500,000,000
Credit facility expiration period	364 days
Proceeds from lines of credit		4,957,000,000
Repayments of lines of credit		4,076,000,000
Credit facility interest rate		1.39%
Debt issuance costs		46,000,000
Senior Bridge Term Loan Agreement, 2013 [Member]
Debt Instrument [Line Items]
Credit facility borrowing capacity				900,000,000	2,100,000,000
Proceeds from lines of credit			900,000,000
Repayments of lines of credit			900,000,000
Credit facility interest rate			1.20%
Debt issuance costs			$ 11,000,000