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Medium- And Long-Term Debt (Schedule Of Medium- And Long-Term Debt) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Medium- and long-term debt		$ 2,796	$ 5,728
Parent Company
Debt Instrument [Line Items]
Medium- and long-term notes		1,471	1,538
Medium- and long-term debt		1,736	1,818
Subsidiaries
Debt Instrument [Line Items]
Subordinated notes		553	587
Medium- and long-term notes		507	523
Long-term Federal Home Loan Bank advances		0	2,800
Medium- and long-term debt		1,060	3,910
3.80% subordinated notes due 2026 | Parent Company
Debt Instrument [Line Items]
Subordinated notes	[1]	$ 265	280
Stated interest rate		3.80%
Maturity year		2026
3.70% notes due 2023 | Parent Company
Debt Instrument [Line Items]
Medium- and long-term notes	[1]	$ 877	905
Stated interest rate		3.70%
Maturity year		2023
4.00% notes due 2029 | Parent Company
Debt Instrument [Line Items]
Medium- and long-term notes	[1]	$ 594	633
Stated interest rate		4.00%
Maturity year		2029
4.00% subordinated notes due 2025 | Subsidiaries
Debt Instrument [Line Items]
Subordinated notes	[1]	$ 363	380
Stated interest rate		4.00%
Maturity year		2025
7.875% subordinated notes due 2026 | Subsidiaries
Debt Instrument [Line Items]
Subordinated notes	[1]	$ 190	207
Stated interest rate		7.875%
Maturity year		2026
2.50% notes due 2024 | Subsidiaries
Debt Instrument [Line Items]
Medium- and long-term notes	[1]	$ 507	523
Stated interest rate		2.50%
Maturity year		2024
Floating-rate based on FHLB auction rate due 2026 | Subsidiaries
Debt Instrument [Line Items]
Long-term Federal Home Loan Bank advances		$ 0	$ 2,800
Maturity year		2026
[1] The fixed interest rates on these notes have been swapped to a variable rate and designated in a hedging relationship. Accordingly, carrying value has been adjusted to reflect the change in the fair value of the debt as a result of changes in the benchmark rate.

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