Schedule of Non-recourse Funding Obligations of Special Purpose Consolidated Captive Insurance Subsidiaries (Detail) - USD ($) $ in Millions		Sep. 30, 2016	Dec. 31, 2015
Nonrecourse Funding Obligations [Line Items]
Non-recourse funding obligations		$ 315	$ 1,935
Deferred borrowing charges		(5)	(15)
Total		310	1,920
River Lake Insurance Company (a), Due 2033
Nonrecourse Funding Obligations [Line Items]
Non-recourse funding obligations	[1]	0	570
River Lake Insurance Company (b), Due 2033
Nonrecourse Funding Obligations [Line Items]
Non-recourse funding obligations	[2]	0	405
River Lake Insurance Company II (a), Due 2035
Nonrecourse Funding Obligations [Line Items]
Non-recourse funding obligations	[1]	0	192
River Lake Insurance Company II (b), Due 2035
Nonrecourse Funding Obligations [Line Items]
Non-recourse funding obligations	[2]	0	453
Rivermont Life Insurance Company I (a), due 2050
Nonrecourse Funding Obligations [Line Items]
Non-recourse funding obligations	[1]	$ 315	$ 315

[1] Accrual of interest based on one-month London Interbank Offered Rate ("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