Summary of Debt Obligations (Parenthetical) (Detail) (USD $)					12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2013 Net Issuance Maturities Of Debt
Debt Disclosure [Line Items]
2013	$ 0
2014	1,199,200,000
2015	2,094,600,000
2016	1,054,200,000
2017	1,003,900,000
Thereafter	8,765,100,000
Reclassification to Long Term Debt	1,200,000,000
Amounts outstanding	14,129,800,000	[1]	13,632,500,000	[1]
Increase (Decrease) In debt obligations					$ 500,000,000

[1] he increase in debt obligations from December 31, 2012 to December 31, 2013 was primarily due to net issuances of $0.5 billion.