Summary of Stock Option and Restricted Stock Activity (Parenthetical) (Detail)	Dec. 31, 2011
Shares available to be issued as restricted stock	13,759,670

Share-based Compensation Arrangement by Share-based Payment Award, Restricted Stock, Available for Additional Grant

No definition available.

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Namespace Prefix:	sti_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant