Background and Business Description AMPS Exchange (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2021	Dec. 31, 2020	May 01, 2013
Stockholders' Equity Attributable to Noncontrolling Interest	$ 60	$ 60
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 16.67
Preferred Stock, Shares Outstanding	0	0
Ambac Assurance Corporation [Member]
Preferred Stock, Liquidation Preference, Value	$ 138	$ 138
Preferred Stock, Shares Outstanding	5,501	5,501