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General (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	$ 8,634		$ 9,348
Mortgage loans	1,021		994
Deferred income taxes	$ 518		$ 199
Accounts receivable, allowance for credit loss		$ 6
CNAF Consolidated \| Loews
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Noncontrolling interest, ownership percentage by parent	89.00%
Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings		5
Mortgage loans		7
Deferred income taxes		$ 2