Investments (Details) - Allowance for Expected Credit Losses $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Allowance for expected credit losses [Roll Forward]
Allowance for expected credit losses on fixed maturities classified as available-for-sale, balance, beginning of period	$ 0
Additions for expected credit losses on securities where no credit losses were previously recognized	10
Additions (reductions) for expected credit losses on securities where credit losses were previously recognized	(6)
Reductions due to sales/defaults of credit-impaired securities	(2)
Reductions for impairments of securities which the Company intends to sell or more likely than not will be required to sell	0
Allowance for expected credit losses on fixed maturities classified as available-for-sale, balance, end of period	2
Credit impairment charges recognized in net realized investment gains on securities which the Company intends to sell and for which an allowance for credit loss was not previously recorded	13
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member]
Allowance for expected credit losses [Roll Forward]
Allowance for expected credit losses on fixed maturities classified as available-for-sale, balance, beginning of period	0
Additions for expected credit losses on securities where no credit losses were previously recognized	0
Additions (reductions) for expected credit losses on securities where credit losses were previously recognized	0
Reductions due to sales/defaults of credit-impaired securities	0
Reductions for impairments of securities which the Company intends to sell or more likely than not will be required to sell	0
Allowance for expected credit losses on fixed maturities classified as available-for-sale, balance, end of period	0
All other corporate bonds [Member]
Allowance for expected credit losses [Roll Forward]
Allowance for expected credit losses on fixed maturities classified as available-for-sale, balance, beginning of period	0
Additions for expected credit losses on securities where no credit losses were previously recognized	10
Additions (reductions) for expected credit losses on securities where credit losses were previously recognized	(6)
Reductions due to sales/defaults of credit-impaired securities	(2)
Reductions for impairments of securities which the Company intends to sell or more likely than not will be required to sell	0
Allowance for expected credit losses on fixed maturities classified as available-for-sale, balance, end of period	$ 2