Long-Term Debt (Detail Textuals) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2014
Final Maturity of 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount, Future Issuance	$ 350
Future Debt Instrument, Interest Rate, Stated Percentage	3.375%
Final Maturity of 2044 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount, Future Issuance	350
Future Debt Instrument, Interest Rate, Stated Percentage	4.30%
Final Maturity of 2015 [Member]
Debt Instrument [Line Items]
Future Extinguishment of Debt, Amount	200
Debt Instrument, Interest Rate, Stated Percentage	4.80%
Final Maturity of 2029 [Member]
Debt Instrument [Line Items]
Future Extinguishment of Debt, Amount	$ 60
Debt Instrument, Interest Rate, Stated Percentage	5.25%