Loan-to-Value of Commercial Mortgage Loans by Property Type (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2014		Dec. 31, 2013
Commercial Mortgage Loans by Credit Quality Indicator [Line Items]
Commercial mortgage loans, recorded investment	$ 6,013		$ 5,932
Greater than 100%
Commercial Mortgage Loans by Credit Quality Indicator [Line Items]
Commercial mortgage loans, recorded investment	119	[1]	106	[2]
Greater than 100% | Loans in Good Standing
Commercial Mortgage Loans by Credit Quality Indicator [Line Items]
Commercial mortgage loans, recorded investment	96		99
Greater than 100% | Loans in Good Standing | Weighted Average Loan-To-Value
Commercial Mortgage Loans by Credit Quality Indicator [Line Items]
Weighted-average loan-to-value	120.00%		119.00%
Greater than 100% | Impaired Loans
Commercial Mortgage Loans by Credit Quality Indicator [Line Items]
Commercial mortgage loans, recorded investment	17		2
Greater than 100% | Delinquent loans
Commercial Mortgage Loans by Credit Quality Indicator [Line Items]
Commercial mortgage loans, recorded investment	$ 6		$ 5

[1] Included $17 million of impaired loans, $6 million of loans past due and not individually impaired and $96 million of loans in good standing, where borrowers continued to make timely payments, with a total weighted-average loan-to-value of 120%.

[2] Included $2 million of impaired loans, $5 million of delinquent loans and $99 million of loans in good standing, where borrowers continued to make timely payments, with a total weighted-average loan-to-value of 119%.