Defined Benefit Plan, Change in Obligations and Fair Value (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Defined Benefit Plan, Fair Value of Plan Assets		$ 3,156		$ 3,025
Defined Benefit Plan, Funded Percentage		110.00%		106.00%
Pension Plan [Member]
Defined Benefit Plan, Benefit Obligation	[1]	$ 2,747	[2]	$ 2,716	[2]	$ 2,935
Defined Benefit Plan, Service Cost	[3]	5	[1]	5	[1]	5
Defined Benefit Plan, Interest Cost	[3]	97	[1]	116	[1]	124
Defined Benefit Plan, Contributions by Plan Participants	[1]	0		0
Defined Benefit Plan, Actuarial Gain (Loss)	[1]	(76)		171
Defined Benefit Plan, Benefits Paid	[1]	(142)		(164)
Defined Contribution Plan, Administrative Expenses	[1]	(5)		(5)
Defined Benefit Plan, Fair Value of Plan Assets	[1]	3,016	[4]	2,879	[4]	3,080
Defined Benefit Plan, Actual Return on Plan Assets	[1]	279		(37)
Defined Benefit Plan, Contributions by Employer	[1]	5		5
Defined Benefit Plan, Funded Status of Plan	[1],[5]	269		163
Defined Benefit Plan, Accumulated Benefit Obligation	[1]	2,747		2,716
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan, Benefit Obligation		58		65		69
Defined Benefit Plan, Service Cost		0		0		0
Defined Benefit Plan, Interest Cost		2		2		3
Defined Benefit Plan, Contributions by Plan Participants		4		6
Defined Benefit Plan, Actuarial Gain (Loss)		4		2
Defined Benefit Plan, Benefits Paid		(9)		(10)
Defined Contribution Plan, Administrative Expenses		0		0
Defined Benefit Plan, Fair Value of Plan Assets		157	[4]	156	[4]	$ 160
Defined Benefit Plan, Actual Return on Plan Assets		5		1
Defined Benefit Plan, Contributions by Employer	[6]	0		0
Defined Benefit Plan, Funded Status of Plan	[7]	99		91
Market Approach Valuation Technique [Member] | Other Postretirement Benefit Plan [Member]
Defined Benefit Plan, Contributions by Plan Participants		$ 5		$ 5

[1] Employer contributions represent the benefits that were paid to nonqualified plan participants. Unfunded nonqualified supplemental pension plans are not funded through plan assets.

[2] Includes $80 million and $81 million of benefit obligations for the unfunded nonqualified supplemental pension plans at December 31, 2016 and 2015, respectively.

[3] Administrative fees are recognized in service cost for each of the periods presented.

[4] Includes $2 million and $1 million of the Company's common stock acquired by the asset manager and held as part of the equity portfolio for pension benefits at December 31, 2016 and 2015, respectively. During both 2016 and 2015, there was no SunTrust common stock held in the other postretirement benefit plans.

[5] Pension benefits recorded in the Consolidated Balance Sheets included other assets of $349 million and $244 million, and other liabilities of $80 million and $81 million, at December 31, 2016 and 2015, respectively.

[6] The Company contributed less than $1 million to the other postretirement benefits plans during both 2016 and 2015.

[7] Other postretirement benefits recorded in the Consolidated Balance Sheets included other assets of $99 million and $91 million at December 31, 2016 and 2015, respectively.