Fair Values of Assets and Liabilities - Losses Recognized Related to Nonrecurring Fair Value Measurements of Individual Assets or Portfolios (Detail) - Fair Value, Measurements, Nonrecurring [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Loans Receivable [Member]
Fair Value Assets Measured On Nonrecurring Basis Losses Recognized [Line Items]
Asset impairment charges	$ 15	$ 31	$ 40	$ 47
Other Assets [Member]
Fair Value Assets Measured On Nonrecurring Basis Losses Recognized [Line Items]
Asset impairment charges	$ 10	$ 15	$ 19	$ 34