Employee Benefit Plans - Rollforward of Pre-tax AOCI (Details) - Pension Plans - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Rollforward of Pre-tax AOCI
Beginning balance	$ (691)	$ (877)	$ (779)
Net gain (loss)	(112)	161	(112)
Prior service cost	0	(2)	0
Amortization of prior service cost	1	1	1
Amortization of net loss	34	26	13
Changes recognized in OCI	(77)	186	(98)
Ending balance	$ (768)	$ (691)	$ (877)

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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- Definition

Amount, before tax, of 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).

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Amount, before tax, of reclassification adjustment from accumulated other comprehensive (income) loss for prior service cost (credit) of defined benefit plan.

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Amount, before tax, after reclassification adjustment, of (increase) decrease in accumulated other comprehensive income for defined benefit plan.

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Amount, before tax, of gain (loss) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Amount, before tax, of reclassification adjustment from accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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