Borrowings (Schedule of Maturities of Long-Term Borrowings) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Schedule of Maturities of Long-Term Debt [Line Items]
Long-term borrowings	$ 2,284	$ 2,407
Parent Company [Member]
Schedule of Maturities of Long-Term Debt [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	0
Long-term Debt, Maturities, Repayments of Principal in Year Two	100
Long-term Debt, Maturities, Repayments of Principal in Year Three	833
Long-term Debt, Maturities, Repayments of Principal in Year Four	0
Long-term Debt, Maturities, Repayments of Principal in Year Five	0
Long-term Debt, Maturities, Repayments of Principal after Year Five	853
Long-term borrowings	1,786	1,909
Regions Bank [Member]
Schedule of Maturities of Long-Term Debt [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	0
Long-term Debt, Maturities, Repayments of Principal in Year Two	0
Long-term Debt, Maturities, Repayments of Principal in Year Three	0
Long-term Debt, Maturities, Repayments of Principal in Year Four	0
Long-term Debt, Maturities, Repayments of Principal in Year Five	0
Long-term Debt, Maturities, Repayments of Principal after Year Five	498
Long-term borrowings	$ 498	$ 498

[Line Items] for Schedule of Maturities of Long-Term Debt [Table]

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