Investments (Mortgage Loans Allowance for Credit Loss Rollforward by Portfolio Segment) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period	$ 634	$ 590
Provision (release)	(18)	(49)
Charge-offs, net of recoveries	(1)	(13)
Balance, end of period	615	528
Commercial Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period	340	252
Provision (release)	(12)	(5)
Charge-offs, net of recoveries	0	0
Balance, end of period	328	247
Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period	206	232
Provision (release)	(21)	(30)
Charge-offs, net of recoveries	(1)	0
Balance, end of period	184	202
Agricultural Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period	88	106
Provision (release)	15	(14)
Charge-offs, net of recoveries	0	(13)
Balance, end of period	$ 103	$ 79