Significant Accounting Policies - Additional Information (Detail) (Troubled Debt Restructuring, Upper Limit, USD $) In Millions	6 Months Ended
Jun. 30, 2011
Troubled Debt Restructuring \| Upper Limit
Significant Accounting Policies [Line Items]
Increase in troubled debt restructuring balance due to change in method	$ 100

Name:

sti_IncreaseInTroubledDebtRestructuringsNewAccountingGuidance

Namespace Prefix:

sti

Data Type:

xbrli:monetaryItemType

Balance Type:

credit

Period Type:

duration