Income Taxes - Reconciliation of income taxes at the statutory rate to the provision for income taxes (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Earnings before income taxes (“EBT”)	$ 219	$ 210	$ 738	$ 777
Income taxes at statutory rate	46	44	155	163
Effect of prior year income taxes	(5)	(3)	(5)	(3)
Effect of tax exempt interest	(2)	(1)	(4)	(5)
Effect of ESOP dividend paid deduction	0	(1)	(3)	(7)
Effect of stock-based compensation	0	0	(2)	(4)
Effect of change in valuation allowance	(2)	2	(2)	1
Effect of dividends received deduction	0	0	(1)	(1)
Effect of nondeductible expenses	3	2	8	5
Effect of foreign operations	2	1	6	6
Effect of other income	0	1	(3)	0
Provision for income taxes as shown on the Statement of Earnings	$ 42	$ 45	$ 149	$ 155
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Income taxes at statutory rate as a percentage of EBT	21.00%	21.00%	21.00%	21.00%
Effect of prior year income taxes as a percentage of EBT	(2.00%)	(2.00%)	(1.00%)	0.00%
Effect of tax exempt interest as a percentage of EBT	(1.00%)	0.00%	(1.00%)	(1.00%)
Effect of ESOP dividend paid deduction as a percentage of EBT	0.00%	0.00%	0.00%	(1.00%)
Effect of stock-based compensation as a percentage of EBT	0.00%	0.00%	0.00%	(1.00%)
Effect of change in valuation allowance as a percentage of EBT	(1.00%)	1.00%	0.00%	0.00%
Effect of dividends received deduction as a percentage of EBT	0.00%	0.00%	0.00%	0.00%
Effect of nondeductible expenses as a percentage of EBT	1.00%	1.00%	1.00%	1.00%
Effect of foreign operations as a percentage of EBT	1.00%	0.00%	1.00%	1.00%
Effect of other income tax reconciliation as a percentage of EBT	0.00%	0.00%	(1.00%)	0.00%
Provision for income taxes as shown on the Statement of Earnings as a percentage of EBT	19.00%	21.00%	20.00%	20.00%

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage 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 changes in the valuation allowance for deferred tax assets.

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