Reserve for Unpaid Losses and Loss Adjustment Expenses - GB Liabilities for Unpaid Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Beginning liabilities for unpaid losses and loss adjustment expenses, gross	$ 39,659
Less: payments
Ending liabilities for unpaid losses and loss adjustment expenses, gross	39,759
Group Insurance Policy [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Beginning liabilities for unpaid losses and loss adjustment expenses, gross	8,210	$ 8,233
Reinsurance recoverables	247	247	$ 245	$ 237
Beginning liabilities for unpaid losses and loss adjustment expenses, net	7,965	7,996
Provision for unpaid losses and loss adjustment expense
Current incurral year	1,324	1,325
Prior year's discount accretion	53	55
Prior incurral year development [1]	(119)	(151)
Total provision for unpaid losses and loss adjustment expenses	1,258	1,229
Less: payments
Current incurral year	(354)	(350)
Prior incurral years	(974)	(914)
Total payments	(1,328)	(1,264)
Beginning liabilities for unpaid losses and loss adjustment expenses, net	7,895	7,961	$ 7,965	$ 7,996
Ending liabilities for unpaid losses and loss adjustment expenses, gross	8,142	8,208
Group Insurance Policy [Member] | Disability Insurance Policy [Member]
Provision for unpaid losses and loss adjustment expense
Prior incurral year development [1]	80	125
Group Insurance Policy [Member] | group life term, disability and accident [Member]
Provision for unpaid losses and loss adjustment expense
Prior incurral year development [1]	35	20
Group Insurance Policy [Member] | Other Operating Income (Expense) [Member]
Provision for unpaid losses and loss adjustment expense
Total provision for unpaid losses and loss adjustment expenses	$ 46	$ 43