Other Debt - Bond Offering (Details) (Unsecured Debt [Member], USD $)	0 Months Ended
	Feb. 07, 2014	Mar. 31, 2014
Senior Unsecured Note [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 2,550,000,000
Debt instrument, redemption price, percentage	100.00%
Debt instrument, unamortized discount (premium), net	4,200,000	4,100,000
Two Percent Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	1,300,000,000
Debt instrument, interest rate, stated percentage	2.00%
Three Percent Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	750,000,000
Debt instrument, interest rate, stated percentage	3.00%
Four Point Six Percent Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 500,000,000
Debt instrument, interest rate, stated percentage	4.60%