Loans Receivable - Summary of Loans Receivable - Regulatory Risk Rating (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 50,927	$ 50,181
Lending Commitments	100,790	98,050
Loans Receivable And Related Lending Commitments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	46,903	46,211
Lending Commitments	100,794	98,045
Total	147,697	144,256
Non-Criticized/Pass [Member] | Loans Receivable And Related Lending Commitments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	43,600	43,146
Lending Commitments	97,205	94,966
Total	140,805	138,112
Criticized [Member] | Loans Receivable And Related Lending Commitments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	3,303	3,065
Lending Commitments	3,589	3,079
Total	$ 6,892	$ 6,144