Employee Benefit Plans (Schedule of Fair Value Measurements By Category) (Detail) - USD ($) $ in Millions		Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		$ 400	$ 360
Common/collective trust funds	[1]	387	387
Total recorded at NAV		387	387
Total investments(2)	[2]	787	747
Level 1
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value			10
Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		400	350
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		1	10
Cash and cash equivalents | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value			10
Cash and cash equivalents | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		1
Corporate Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		332	315
Corporate Debt Securities | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		332	315
Government and Other Debt Instruments
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		67	35
Government and Other Debt Instruments | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		$ 67	$ 35

[1] These investments that are measured at fair value using the NAV per share (or its equivalent) as a practical expedient are not required to be categorized in the fair value hierarchy

[2] Excludes net assets related to pending sales of securities of $4 million, net accrued income of $2 million, and includes net assets related to pending purchases of securities of $25 million at December 31, 2021.