Allowance for Expected Credit Losses (Details) - Changes in the Allowance for Expected Credit Losses on Contractholder Receivables (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Credit Loss [Abstract]
Contractholder receivables (net of the allowance for expected credit losses), balance, beginning of period	$ 4,242	$ 4,599
Contractholder receivables (net of the allowance for expected credit losses), balance, end of period	4,271	4,242
Contractholder receivables, allowance for expected credit losses [Roll Forward]
Contractholder receivables, allowance for expected credit losses, beginning balance	19	20
Current period change for expected credit losses	0	1
Write-offs of uncollectible contractholder receivables	0	2
Contractholder receivables, allowance for expected credit losses, ending balance	$ 19	$ 19