Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Amortization for qualifying LIHTC investments	$ 200,000,000	$ 189,000,000	$ 163,000,000
Deferred tax assets related to state net operating loss carryforwards	11,000,000	14,000,000
State net operating loss carryforwards specific valuation allowances	5,000,000	5,000,000
Interest expense recognized in connection with income taxes	2,000,000	1,000,000	$ 1,000,000
Accrued interest liabilities, net of the related tax benefits	10,000,000	8,000,000
Liabilities for penalties related to income taxes	0	0
Allocation of earnings for bad debt deductions of former thrift subsidiaries included in retained earnings	$ 157,000,000	$ 157,000,000

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- Definition

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-6

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-Section 50
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-Publisher FASB
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- Definition

The amount of estimated interest recognized in the period arising from income tax examinations.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-15

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to investment tax credit.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-12

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The portion of the valuation allowance pertaining to the deferred tax asset representing potential future taxable deductions from net operating loss carryforwards for which it is more likely than not that a tax benefit will not be realized.

+ References

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- Definition

Amount of statutory penalties accrued for a tax position claimed or expected to be claimed by the entity, in its tax return.

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Amount of interest expense accrued for an underpayment of income taxes.

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