Summary of Significant Accounting Policies - Leases (Details) $ in Millions	Sep. 30, 2023 USD ($)
Summary of Significant Accounting Policies
Financing Receivable , Individually Evaluated for Losses ,Net Book Balance	$ 1

The threshold amount of net book balance of financing receivable individually evaluated for losses.

No definition available.

Name:	ssb_FinancingReceivableIndividuallyEvaluatedForLossesThresholdNetBookBalance
Namespace Prefix:	ssb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant