Loans Receivable - Summary of Loans Receivable - Regulatory Risk Rating (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 49,555	$ 45,821
Lending Commitments	91,150	93,920
Loans Receivable And Related Lending Commitments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	46,467	43,700
Lending Commitments	91,155	93,919
Total	137,622	137,619
Non-Criticized/Pass [Member] | Loans Receivable And Related Lending Commitments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	43,419	40,967
Lending Commitments	87,830	92,021
Total	131,249	132,988
Criticized [Member] | Loans Receivable And Related Lending Commitments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	3,048	2,733
Lending Commitments	3,325	1,898
Total	$ 6,373	$ 4,631