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Employee Benefit Plans (Summary of Changes in the Corporation's Qualified Defined Benefit Pension Plan's Level 3 Investments Measured at Fair Value on a Recurring Basis) (Details) - Private placements - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Balance at beginning and end of period	$ 44	$ 39
Gains (Losses) Realized	0	(3)
Gains (Losses) Unrealized	(2)	8
Purchases	47	46
Sales	(52)	(46)
Balance at beginning and end of period	$ 37	$ 44

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Balance at beginning and end of period

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This element represents total realized gains or losses for the period, arising from assets measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in earnings or resulted in a change in net asset value.

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This element represents total unrealized gains or losses for the period, arising from assets measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in earnings or resulted in a change in net asset value.

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Purchases

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