Derivative Instruments - Summary of Location and Amount of Gains and Losses of Derivative Contracts (Detail) (USD $) In Thousands, unless otherwise specified	8 Months Ended	12 Months Ended	4 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2014	Apr. 30, 2013	Dec. 31, 2012
Successor [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	$ 802,462	$ (585,038)
Predecessor [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total			(297,855)	(168,242)
Net Change in Fair Value of Credit Derivatives [Member] | Successor [Member] | Credit Derivatives [Member] | Financial Guarantee [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	192,869	23,906
Net Change in Fair Value of Credit Derivatives [Member] | Predecessor [Member] | Credit Derivatives [Member] | Financial Guarantee [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total			(60,384)	(9,219)
Derivative Products [Member] | Successor [Member] | Financial Services Derivatives Products [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	114,771	(181,087)
Derivative Products [Member] | Successor [Member] | Interest Rate Swaps [Member] | Financial Services Derivatives Products [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	104,114	(173,595)
Derivative Products [Member] | Successor [Member] | Currency Swaps [Member] | Financial Services Derivatives Products [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	0	0
Derivative Products [Member] | Successor [Member] | Futures Contracts [Member] | Financial Services Derivatives Products [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	10,925	(7,472)
Derivative Products [Member] | Successor [Member] | Other Contracts [Member] | Financial Services Derivatives Products [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	(268)	(20)
Derivative Products [Member] | Predecessor [Member] | Financial Services Derivatives Products [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total			(33,735)	(125,004)
Derivative Products [Member] | Predecessor [Member] | Interest Rate Swaps [Member] | Financial Services Derivatives Products [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total			(30,622)	(111,396)
Derivative Products [Member] | Predecessor [Member] | Currency Swaps [Member] | Financial Services Derivatives Products [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total			0	807
Derivative Products [Member] | Predecessor [Member] | Futures Contracts [Member] | Financial Services Derivatives Products [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total			(3,133)	(14,864)
Derivative Products [Member] | Predecessor [Member] | Other Contracts [Member] | Financial Services Derivatives Products [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total			20	449
Other Income [Member] | Predecessor [Member] | Call Options on Long-Term Debt [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total			0	100,710
Income Loss On Variable Interest Entities [Member] | Successor [Member] | Variable Interest Entity [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	494,822	(427,857)
Income Loss On Variable Interest Entities [Member] | Successor [Member] | Interest Rate Swaps [Member] | Variable Interest Entity [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	495,712	(452,434)
Income Loss On Variable Interest Entities [Member] | Successor [Member] | Currency Swaps [Member] | Variable Interest Entity [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total	(890)	24,577
Income Loss On Variable Interest Entities [Member] | Predecessor [Member] | Variable Interest Entity [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total			(203,736)	(134,729)
Income Loss On Variable Interest Entities [Member] | Predecessor [Member] | Interest Rate Swaps [Member] | Variable Interest Entity [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total			(203,620)	(107,341)
Income Loss On Variable Interest Entities [Member] | Predecessor [Member] | Currency Swaps [Member] | Variable Interest Entity [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative instruments, gain (loss) recognized in income, net, Total			$ (116)	$ (27,388)