Income Taxes - Reconciliation of income taxes at the statutory rate to the provision for income taxes (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Earnings (loss) before income taxes (“EBT”)	$ 218	$ 259	$ (170)	$ 672
Income taxes at statutory rate	45	54	(36)	141
Effect of tax exempt interest	(3)	(3)	(6)	(7)
Effect of stock-based compensation	0	(2)	(4)	(4)
Effect of dividends received deduction	0	(1)	(1)	(2)
Effect of employee stock ownership plan dividend paid deduction	0	(1)	0	(1)
Effect of change in valuation allowance	9	1	11	3
Effect of nondeductible expenses	0	2	2	4
Effect of foreign operations	0	0	1	0
Effect of other income tax reconciliation	0	0	0	3
Provision for income taxes as shown on the Statement of Earnings	$ 51	$ 50	$ (33)	$ 137
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 tax exempt interest as a percentage of EBT	(1.00%)	(1.00%)	4.00%	(1.00%)
Effect of stock-based compensation as a percentage of EBT	0.00%	(1.00%)	2.00%	(1.00%)
Effect of dividends received deduction as a percentage of EBT	0.00%	0.00%	1.00%	0.00%
Effect of dividends received deduction as a percentage of EBT	0.00%	0.00%	0.00%	0.00%
Effect of change in valuation allowance as a percentage of EBT	4.00%	0.00%	(6.00%)	0.00%
Effect of nondeductible expenses as a percentage of EBT	0.00%	1.00%	(1.00%)	1.00%
Effect of foreign operations as a percentage of EBT	0.00%	0.00%	(1.00%)	0.00%
Effect of other income tax reconciliation as a percentage of EBT	(1.00%)	(1.00%)	(1.00%)	0.00%
Provision for income taxes as shown on the Statement of Earnings as a percentage of EBT	23.00%	19.00%	19.00%	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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Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

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