Schedule of Non-recourse Funding Obligations of Special Purpose Consolidated Captive Insurance Subsidiaries (Detail) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Nonrecourse Funding Obligations [Line Items]
Subtotal		$ 1,935	$ 1,996
Deferred borrowing charges		(15)	(15)
Non-recourse funding obligations		1,920	1,981
River Lake Insurance Company (a), Due 2033
Nonrecourse Funding Obligations [Line Items]
Subtotal	[1]	570	570
River Lake Insurance Company (b), Due 2033
Nonrecourse Funding Obligations [Line Items]
Subtotal	[2]	405	435
River Lake Insurance Company II (a), Due 2035
Nonrecourse Funding Obligations [Line Items]
Subtotal	[1]	192	192
River Lake Insurance Company II (b), Due 2035
Nonrecourse Funding Obligations [Line Items]
Subtotal	[2]	453	484
Rivermont Life Insurance Company I (a), due 2050
Nonrecourse Funding Obligations [Line Items]
Subtotal	[1]	$ 315	$ 315

[1] Accrual of interest based on one-month LIBOR that resets every 28 days plus a fixed margin.

[2] Accrual of interest based on one-month LIBOR that resets on a specified date each month plus a contractual margin