Investments (Rollforward of the Allowance for Credit Losses for Mortgage Loans by Portfolio Segment) (Details) - Mortgage Loans - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing receivable, allowance for credit losses, beginning of period	$ 123	$ 94
Current period provision	4	(4)
Financing receivable, allowance for credit losses, end of period	127	90
Commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing receivable, allowance for credit losses, beginning of period	67	44
Current period provision	2	1
Financing receivable, allowance for credit losses, end of period	69	45
Agricultural
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing receivable, allowance for credit losses, beginning of period	12	15
Current period provision	3	(2)
Financing receivable, allowance for credit losses, end of period	15	13
Residential
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing receivable, allowance for credit losses, beginning of period	44	35
Current period provision	(1)	(3)
Financing receivable, allowance for credit losses, end of period	$ 43	$ 32