Employee Benefit Plans and Equity Compensation Plan (Funded Status) (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 725	$ 677	$ 781
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	725	676
Benefit obligation	727	732	793
Funded status	(2)	(56)
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation	214	187	$ 217
Funded status	$ (214)	$ (187)

Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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+ 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

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-Publisher FASB
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- Definition

Amount of funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status.

+ References

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