Financing Receivables - Residential Mortgage Loans by Region (Details) - Consumer Loans - Residential mortgage loans - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2024	Dec. 31, 2023
Financing receivables - credit quality information
Loans	$ 332	$ 300
Total residential mortgage loans \| Credit concentration risk
Financing receivables - credit quality information
Percentage of total	100.00%	100.00%
Minnesota
Financing receivables - credit quality information
Loans	$ 200	$ 178
Minnesota \| Total residential mortgage loans \| Credit concentration risk
Financing receivables - credit quality information
Percentage of total	60.00%	59.00%
Other U.S. States
Financing receivables - credit quality information
Loans	$ 132	$ 122
Other U.S. States \| Total residential mortgage loans \| Credit concentration risk
Financing receivables - credit quality information
Percentage of total	40.00%	41.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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