Derivative Financial Instruments (Hedged Items In Fair Value Hedges) (Details) - USD ($)	Mar. 31, 2026	Dec. 31, 2025
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Carrying value of the hedged items, available for sale debt securities	$ 7,384,000,000	$ 7,674,800,000
Cumulative hedge accounting basis adjustment, available for sale debt securities	41,100,000	94,100,000
Carrying value of the hedged items, senior notes and long-term subordinated debt	3,081,800,000	3,091,100,000
Cumulative hedge accounting basis adjustment, senior notes and long-term subordinated debt	(161,000,000.0)	(151,400,000)
Hedged asset fair value hedge discontinued cumulative increase decrease	1,200,000	1,300,000
Hedged liability fair value hedge discontinued cumulative increase decrease	$ 0	$ 0