Credit Loss Reserves - Summarizes Changes in Credit Loss Reserves by Product/Class and Related Receivable Balance by Product - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016		Mar. 31, 2015
Financing Receivable, Allowance for Credit Losses [Line Items]
Initial lower of amortized cost or fair value adjustment(2)		$ 17		$ 0
Write-offs	[1]	79	[2]	147
Excludes Credit loss reserves for TDR Loans that are carried at the lower of amortized cost or fair value		9		22
TDR [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Excludes TDR loans that are carried at the lower of amortized cost or fair value		211		399
Real Estate Secured Receivable Portfolio [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Write-offs		20		15
Mortgage Receivable [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Release of provision associated with a correction to the reserve calculation for a segment of the portfolio				$ 19
First and Second Mortgage [Member] | Fair Value [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Initial lower of amortized cost or fair value adjustment(2)		$ 13

[1] For collateral dependent receivables that are transferred to held for sale, existing credit loss reserves at the time of transfer are recognized as a charge-off. We transferred to held for sale certain real estate secured receivables during the three months ended March 31, 2016 and 2015 and, accordingly, we recognized the existing credit loss reserves on these receivables as additional charge-off totaling $20 million during the three months ended March 31, 2016 compared with $15 million during the three months ended March 31, 2015.

[2] The provision for credit losses and charge-offs for real estate secured receivables during the three months ended March 31, 2016 include $13 million related to the lower of amortized cost or fair value adjustment attributable to credit factors for receivables transferred to held for sale. See Note 5, "Receivables Held for Sale," for additional information. The provision for credit losses for real estate secured receivables during the three months ended March 31, 2015 was impacted by a release of approximately $19 million associated with a correction to our credit loss reserve calculation for a segment of our portfolio.