Long-Term Debt (Narrative) (Details) - USD ($) $ in Millions				12 Months Ended
	Sep. 15, 2023	Nov. 15, 2018	May 15, 2014	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Senior Notes				$ 153
Extinguishment of Debt, Amount				0	$ 1	$ 3
Capital Lease Obligations				$ 1	1
Junior Subordinated Notes					165
Long-term Debt, Interest Rate 6.95%				6.95%
Long-Term Debt, Interest Rate 5.65%				5.65%
Stock Redeemed or Called During Period, Value				$ 144	(126)	$ (176)
Subordinated debt converted to preferred stock					(90)
Senior medium-term notes				135	$ 288
Long-term debt, Parent only maturities				382
Parent Company [Member]
Debt Instrument [Line Items]
Long-term debt, Parent only maturities				$ 382
Subordinated Notes Interest Rate 5.65 Percent [Member]
Debt Instrument [Line Items]
New interest rate		3mL+4.19%
Interest payments begin			May 15, 2014
Subordinated Notes Interest Rate 6.95 Percent [Member]
Debt Instrument [Line Items]
New interest rate	3mL+3.89%