Capital - Additional Information (Details) - USD ($)		3 Months Ended	6 Months Ended	12 Months Ended
		Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2009	Nov. 30, 2014	Sep. 30, 2011	Sep. 22, 2011	Dec. 31, 2008	Sep. 30, 2006
Schedule of Capitalization, Equity [Line Items]
Stock Issued During Period, Value, New Issues						$ 496,000,000
Common Stock, Dividends, Per Share, Cash Paid		$ 0.26	$ 0.24	$ 1.00	$ 0.92	$ 0.70
Dividends, Common Stock, Cash				$ (498,000,000)	$ (475,000,000)	$ (371,000,000)
Dividends, Preferred Stock, Cash	[1]			$ (66,000,000)	$ (64,000,000)	(42,000,000)
Dividend Per Quarter Threshold Prior To Tenth Anniversay Triggering Execise Of Warrants				$ 0.54
Tier One Risk Based Capital to Risk Weighted Assets				10.28%	10.80%
Cash Reserve Deposit Required and Made				$ 1,300,000,000	$ 1,000,000,000
Common Equity Tier 1 to Risk Weighted Assets				9.59%	9.96%
Capital to Risk Weighted Assets				12.26%	12.54%
Tier One Leverage Capital to Average Assets				9.22%	9.69%
Preferred Stock, Shares Authorized				50,000,000	50,000,000
Stock Issued During Period, Value, New Issues				$ 0	$ 0	496,000,000
Class of Warrant or Right, Outstanding				7,400,000
Payments for Repurchase of Warrants				$ 24,000,000	$ 0	$ 0
Common Stock [Member]
Schedule of Capitalization, Equity [Line Items]
Stock Repurchased During Period, Value			$ 350,000,000	480,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount				$ 480,000,000
Stock Repurchased During Period, Shares				11,000,000
Series A Preferred Stock [Member]
Schedule of Capitalization, Equity [Line Items]
Preferred Stock, Dividends, Per Share, Cash Paid				$ 4,067	$ 4,056	$ 4,056
Preferred Stock, Shares Authorized														5,000
Preferred Stock, Shares Issued														5,000
Preferred Stock, No Par Value														$ 0
Preferred Stock, Liquidation Preference, Value														$ 100,000
Declared And Accrued Preferred Stock Dividend Basis Spread on Variable Rate				0.53%
Declared And Accrued Preferred Stock Dividend Fixed Rate				4.00%
Stock Redeemed or Called During Period, Shares									3,275
Preferred Stock, Redemption Price Per Share											$ 100,000
Series B Preferred Stock [Member]
Schedule of Capitalization, Equity [Line Items]
Preferred Stock, Dividends, Per Share, Cash Paid				$ 4,067	4,056	4,056
Preferred Stock, Shares Authorized								5,010
Preferred Stock, Shares Issued								1,025
Preferred Stock, No Par Value								$ 0
Preferred Stock, Liquidation Preference, Value								$ 100,000
Declared And Accrued Preferred Stock Dividend Basis Spread on Variable Rate				0.65%
Declared And Accrued Preferred Stock Dividend Fixed Rate				4.00%
Preferred Stock, Redemption Price Per Share								$ 100,000
Series E Preferred Stock [Member]
Schedule of Capitalization, Equity [Line Items]
Preferred Stock, Dividends, Per Share, Cash Paid				$ 5,875	$ 5,875	$ 5,875
Preferred Stock, Shares Authorized							5,000
Preferred Stock, Shares Issued							4,500
Preferred Stock, No Par Value							$ 0
Preferred Stock, Liquidation Preference, Value							$ 100,000
Declared And Accrued Preferred Stock Dividend Fixed Rate							5.88%
Preferred Stock, Redemption Price Per Share							$ 100,000
Series F Preferred Stock [Member]
Schedule of Capitalization, Equity [Line Items]
Preferred Stock, Shares Issued										5,000
Preferred Stock, No Par Value										$ 0
Preferred Stock, Liquidation Preference, Value										$ 100,000
Declared And Accrued Preferred Stock Dividend Basis Spread on Variable Rate				3.86%
Declared And Accrued Preferred Stock Dividend Fixed Rate				5.63%
Preferred Stock, Redemption Price Per Share										$ 100,000
Sun Trust Bank [Member]
Schedule of Capitalization, Equity [Line Items]
Retained Earnings, Unappropriated				$ 2,500,000,000	$ 2,700,000,000
Parent Company [Member]
Schedule of Capitalization, Equity [Line Items]
Dividends, Preferred Stock, Cash				(66,000,000)	(64,000,000)	$ (42,000,000)
Stock Issued During Period, Value, New Issues				0	0	496,000,000
Payments for Repurchase of Warrants				24,000,000	0	0
Parent Company [Member] | Junior Subordinated Debt [Member]
Schedule of Capitalization, Equity [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Amount				$ 627,000,000	$ 627,000,000
Series A [Member]
Schedule of Capitalization, Equity [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights													6,000,000
Class of Warrant or Right, Exercise Price of Warrants or Rights													$ 33.70
warrants purchased				1,000,000				4,000,000
Payments for Repurchase of Warrants								$ 11,000,000
Series B [Member]
Schedule of Capitalization, Equity [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights													11,900,000
Class of Warrant or Right, Exercise Price of Warrants or Rights													$ 44.15
warrants purchased				5,000,000
Warrant [Member]
Schedule of Capitalization, Equity [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights												17,900,000
Long-term Debt [Member] | Parent Company [Member] | Junior Subordinated Debt [Member]
Schedule of Capitalization, Equity [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Amount				$ 627,000,000
Minimum [Member]
Schedule of Capitalization, Equity [Line Items]
Tier One Risk Based Capital to Risk Weighted Assets				6.00%
Common Equity Tier 1 to Risk Weighted Assets				4.50%
Capital to Risk Weighted Assets				8.00%
Tier One Leverage Capital to Average Assets				4.00%
Capital Required for Capital Adequacy to Risk Weighted Assets				2.50%
Additional Paid-in Capital [Member]
Schedule of Capitalization, Equity [Line Items]
Stock Issued During Period, Value, New Issues						$ 4,000,000
Payments for Repurchase of Warrants				$ 24,000,000
Additional Paid-in Capital [Member] | Series F Preferred Stock [Member]
Schedule of Capitalization, Equity [Line Items]
Preferred Stock, Dividends, Per Share, Cash Paid				$ 5,625	$ 6,219

[1] For the year ended December 31, 2016, dividends were $4,067 per share for both Perpetual Preferred Stock Series A and B, $5,875 per share for Perpetual Preferred Stock Series E, and $5,625 per share for Perpetual Preferred Stock Series F.For the year ended December 31, 2015, dividends were $4,056 per share for both Perpetual Preferred Stock Series A and B, $5,875 per share for Perpetual Preferred Stock Series E, and $6,219 per share for Perpetual Preferred Stock Series F.