Employee Benefit Plans - Rollforward of the Benefit Obligation and Fair Value of Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Amounts recognized in the balance sheet
Liabilities	$ (17)	$ (19)
Pension Plans
Rollforward of projected benefit obligation
Benefit obligation at beginning of year	4,334	4,026
Service cost	19	17	$ 16
Interest cost	104	121	139
Actuarial loss (gain)	(122)	362
Plan amendments	(1)	2
Plan settlements	(16)	(2)
Benefits paid	(217)	(222)
Other	(20)	30
Benefit obligation at end of year	4,081	4,334	4,026
Rollforward of fair value of plan assets
Balance at beginning of period	3,985	3,553
Actual return on plan assets	(186)	600
Employer contributions	38	35
Benefits paid	(217)	(222)
Plan settlements	(15)	(2)
Other	0	21
Balance at end of period	3,605	3,985	$ 3,553
Funded (unfunded) status	(476)	(349)
Amounts recognized in the balance sheet
Assets	117	283
Liabilities	(593)	(632)
Net amount recognized	$ (476)	$ (349)

Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses.

Name:	us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan.