Retirement Plans - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Settlement loss			$ 0	$ 93	$ 4
Budgeted contributions to funded pension plans for next year			4
Expense for defined contribution plans			$ 22	20	19
Scenario Forecast
Defined Benefit Plan Disclosure [Line Items]
Service costs		$ 55
Net non-service pension costs		85
Interest costs		55
Amortization of unrecognized net actuarial losses		(55)
Expected return on plan assets		$ 195
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Current target allocations for plan assets			45.00%
Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Current target allocations for plan assets			35.00%
Other Types of Investments
Defined Benefit Plan Disclosure [Line Items]
Current target allocations for plan assets			20.00%
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Single premium annuity contract cost				249
Settlement loss	$ (88)		$ 0	93	4
Service costs			50	44	42
Interest costs			73	89	91
Amortization of unrecognized net actuarial losses			48	52	39
Expected return on plan assets			$ 180	$ 180	$ 194