Allowance for Expected Credit Losses (Details) - Changes in the Allowance for Expected Credit Losses on Contractholder Receivables (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Credit Loss [Abstract]
Contractholder receivables (net of the allowance for expected credit losses), balance, beginning of period	$ 4,016	$ 4,314	$ 4,242	$ 4,599
Contractholder receivables (net of the allowance for expected credit losses), balance, end of period	4,024	4,347	4,024	4,347
Contractholder receivables, allowance for expected credit losses [Roll Forward]
Contractholder receivables, allowance for expected credit losses, beginning balance	19	22	19	20
Current period change for expected credit losses	0	0	0	2
Write-offs of uncollectible contractholder receivables	0	1	0	1
Contractholder receivables, allowance for expected credit losses, ending balance	$ 19	$ 21	$ 19	$ 21