Insurance (Obligations Under Funding Agreements - FHLB Common Stock) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal Home Loan Bank Stock	$ 814	$ 809
Federal Home Loan Bank of New York
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal Home Loan Bank Stock	812	737
Federal Home Loan Bank of Des Moines
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal Home Loan Bank Stock	2	4
Federal Home Loan Bank of Pittsburgh
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal Home Loan Bank Stock	$ 0	$ 35