Retirement Benefits (Details 4) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Pension plans with accumulated benefit obligations in excess of fair value of plan assets (Table Amounts) [Abstract]
Projected benefit obligation	$ 30,259	$ 29,804
Accumulated benefit obligation	29,961	29,454
Fair value of plan assets	$ 25,101	$ 24,981

No definition available.

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- Definition

Amount of accumulated benefit obligation for defined benefit plan with accumulated benefit obligation in excess of plan assets.

+ References

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-Publisher FASB
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- Definition

Amount of plan asset for defined benefit plan with accumulated benefit obligation in excess of plan assets.

+ References

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-Publisher FASB
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- Definition

Amount of projected benefit obligation for defined benefit pension plan with accumulated benefit obligation in excess of plan assets.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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