Regulation and Capital Adequacy - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital conservation buffer	0.625%
Global Systemically Important Bank (G-SIB) buffer	0.75%
Counter-cyclical capital buffer	0.00%
G-SIB buffer	3.00%
Confidence level for regulatory VaR	99.00%
Confidence level for risk management VaR	95.00%
Time horizon for regulatory VaR (in days)	10 days
Time horizon for risk management VaR (in days)	1 day
Increased deductions due to transitional provisions, percentage	60.00%	40.00%	20.00%
Minimum equity capital that is required to be maintained in regulated subsidiaries	$ 47,470	$ 48,090
Standardized Capital Rules [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Change in Credit RWAs	815	(52,577)
Change in Market RWAs	(11,902)	(42,532)
Basel III Advanced Transitional [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Change in Credit RWAs	18,527	16,138
Change in Market RWAs	(11,719)	(41,900)
Change in Operational RWAs	(4,463)	33,100
GS&Co [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Regulatory net capital as defined by Rule 15c3-1	17,650	14,750
Excess amount of regulatory net capital as defined by Rule 15c3-1	15,240	12,370
Amount of broker-dealer tentative net capital required to be held in accordance with Appendix E of Rule 15c3-1	1,000
Amount of broker-dealer net capital required to be held in accordance with Appendix E of Rule 15c3-1	500
Minimum tentative net capital required to be maintained by GS&Co or must notify the SEC	5,000
GSEC [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Regulatory net capital as defined by Rule 15c3-1	139	1,710
Excess amount of regulatory net capital as defined by Rule 15c3-1	$ 138	1,590
GS Bank USA [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital conservation buffer	0.625%
Counter-cyclical capital buffer	0.00%
Amount deposited by GS Bank USA held at the Federal Reserve Bank of New York	$ 66,660	49,360
Excess amount deposited by GS Bank USA held at the Federal Reserve Bank of New York	$ 66,590	$ 49,250