Basis of Presentation and Significant Accounting Policies Noncontrolling Interest (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($)
Stockholders' Equity Attributable to Noncontrolling Interest	$ 53	$ 60
Preferred Stock, Shares Outstanding | shares	0	0
Redeemable Noncontrolling Interest, Equity, Carrying Amount	$ 20	$ 18	$ 7
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value	5	0
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest	(1)	(1)
Temporary Equity, Accretion to Redemption Value, Adjustment	$ (3)	$ 12
AMPS Shares Purchased	(905)
AMPS Gain Based on Carry Value	$ 1
AMPS Purchase Cash Paid	$ 8
Ambac Assurance Corporation [Member]
Preferred Stock, Shares Outstanding | shares	4,596	5,501
Preferred Stock, Liquidation Preference, Value	$ 115	$ 138
Xchange
Business Acquisition, Percentage of Voting Interests Acquired	80.00%
Capacity Marine
Business Acquisition, Percentage of Voting Interests Acquired	80.00%
All Trans
Business Acquisition, Percentage of Voting Interests Acquired	85.00%
London Interbank Offered Rate (LIBOR) [Member]
Dividend Rate on Auction Rate Preferred Shares	200