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Employee Benefit Plans (Fair Values of the Corporation's Qualified Defined Benefit Pension Plan Investments Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Fair value of plan assets in qualified defined benefit pension plan, Excluding assets valued at net asset value	$ 1,397	$ 1,269
Fair value of plan assets in qualified defined benefit pension plan	2,665	2,499
Debt securities | U.S. Treasury and other U.S. government agency securities
Fair value of plan assets in qualified defined benefit pension plan	567	534
Debt securities | Corporate and municipal bonds and notes
Fair value of plan assets in qualified defined benefit pension plan	786	676
Debt securities | Mortgage-backed secutities
Fair value of plan assets in qualified defined benefit pension plan		20
Debt securities | Collective investments funds
Fair value of plan assets in qualified defined benefit pension plan	1,268	1,230
Private placements | Private placements
Fair value of plan assets in qualified defined benefit pension plan	44	39
Level 1
Fair value of plan assets in qualified defined benefit pension plan, Excluding assets valued at net asset value	564	531
Level 1 | Debt securities | U.S. Treasury and other U.S. government agency securities
Fair value of plan assets in qualified defined benefit pension plan	564	531
Level 1 | Debt securities | Corporate and municipal bonds and notes
Fair value of plan assets in qualified defined benefit pension plan	0	0
Level 1 | Debt securities | Mortgage-backed secutities
Fair value of plan assets in qualified defined benefit pension plan		0
Level 1 | Private placements
Fair value of plan assets in qualified defined benefit pension plan	0
Level 1 | Private placements | Private placements
Fair value of plan assets in qualified defined benefit pension plan		0
Level 2
Fair value of plan assets in qualified defined benefit pension plan, Excluding assets valued at net asset value	789	699
Level 2 | Debt securities | U.S. Treasury and other U.S. government agency securities
Fair value of plan assets in qualified defined benefit pension plan	3	3
Level 2 | Debt securities | Corporate and municipal bonds and notes
Fair value of plan assets in qualified defined benefit pension plan	786	676
Level 2 | Debt securities | Mortgage-backed secutities
Fair value of plan assets in qualified defined benefit pension plan		20
Level 2 | Private placements
Fair value of plan assets in qualified defined benefit pension plan	0
Level 2 | Private placements | Private placements
Fair value of plan assets in qualified defined benefit pension plan		0
Level 3
Fair value of plan assets in qualified defined benefit pension plan, Excluding assets valued at net asset value	44	39
Level 3 | Debt securities | U.S. Treasury and other U.S. government agency securities
Fair value of plan assets in qualified defined benefit pension plan	0	0
Level 3 | Debt securities | Corporate and municipal bonds and notes
Fair value of plan assets in qualified defined benefit pension plan	0	0
Level 3 | Debt securities | Mortgage-backed secutities
Fair value of plan assets in qualified defined benefit pension plan		0
Level 3 | Private placements | Private placements
Fair value of plan assets in qualified defined benefit pension plan	$ 44	$ 39

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- Definition

Total assets at fair value in the fair value hierarchy valued on a nonrecurring basis.

+ References

No definition available.

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- Definition

Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 20
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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