Income Taxes - Reconciliation of income taxes at the statutory rate to the provision for income taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Earnings (loss) before income taxes (“EBT”)	$ (388)	$ 413
Income taxes at statutory rate	(81)	87
Effect of stock-based compensation	(4)	(2)
Effect of tax exempt interest	(3)	(4)
Effect of dividends received deduction	(1)	(1)
Effect of nondeductible expenses	2	2
Effect of change in valuation allowance	2	2
Effect of foreign operations	1	0
Effect of other income tax reconciliation	0	3
Provision for income taxes as shown on the Statement of Earnings	$ (84)	$ 87
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Income taxes at statutory rate as a percentage of EBT	21.00%	21.00%
Effect of stock-based compensation as a percentage of EBT	1.00%	0.00%
Effect of tax exempt interest as a percentage of EBT	1.00%	(1.00%)
Effect of dividends received deduction as a percentage of EBT	0.00%	0.00%
Effect of nondeductible expenses as a percentage of EBT	(1.00%)	0.00%
Effect of change in valuation allowance as a percentage of EBT	(1.00%)	0.00%
Effect of foreign operations as a percentage of EBT	0.00%	0.00%
Effect of other income tax reconciliation as a percentage of EBT	1.00%	1.00%
Provision for income taxes as shown on the Statement of Earnings as a percentage of EBT	22.00%	21.00%