Share-based Compensation and Employee Benefits - Schedule of Components of Accumulated Other Comprehensive (Loss) Income (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Unrecognized net actuarial (loss) gain	$ (557)	$ (653)
Unrecognized prior service (cost) credit	(3)	(3)
Accumulated other comprehensive (loss) income	(560)	(656)
OPEB
Defined Benefit Plan Disclosure [Line Items]
Unrecognized net actuarial (loss) gain	123	117
Unrecognized prior service (cost) credit	12	14
Accumulated other comprehensive (loss) income	$ 135	$ 131

Amount, before tax, of accumulated other comprehensive (income) loss for defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
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Amount, before tax, of accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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Amount, before tax, of accumulated other comprehensive (income) loss for cost (credit) of benefit change attributable to participants' prior service from plan amendment or plan initiation of defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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