Employee Benefit Plans (Fair Values of the Company's Pension Plan Assets by Asset Category) (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	$ 2,975	$ 3,216
Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	2,358	2,506
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	333	338
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	1,071	1,252
Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	954	916	$ 835
Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	617	710
Defined Benefit Plan, Equity Securities, US, Large Cap | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	157	159
Defined Benefit Plan, Equity Securities, US, Large Cap | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	79	65
Defined Benefit Plan, Equity Securities, US, Large Cap | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	78	94
Defined Benefit Plan, Equity Securities, US, Large Cap | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
Defined Benefit Plan, Equity Securities, US, Small Cap | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	48	42
Defined Benefit Plan, Equity Securities, US, Small Cap | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	48	42
Defined Benefit Plan, Equity Securities, US, Small Cap | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
Defined Benefit Plan, Equity Securities, US, Small Cap | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
Defined Benefit Plan, Equity Securities, Non-US | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	206	224
Defined Benefit Plan, Equity Securities, Non-US | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	130	144
Defined Benefit Plan, Equity Securities, Non-US | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	76	80
Defined Benefit Plan, Equity Securities, Non-US | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
Defined Benefit Plan, Cash and Cash Equivalents | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	50	15
Defined Benefit Plan, Cash and Cash Equivalents | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	8	5
Defined Benefit Plan, Cash and Cash Equivalents | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	42	10
Defined Benefit Plan, Cash and Cash Equivalents | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
Debt Security, Corporate, US | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	332	464
Debt Security, Corporate, US | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
Debt Security, Corporate, US | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	232	386
Debt Security, Corporate, US | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	100	78
Debt Security, Developed Markets And Emerging Economies | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	1	2
Debt Security, Developed Markets And Emerging Economies | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
Debt Security, Developed Markets And Emerging Economies | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	1	2
Debt Security, Developed Markets And Emerging Economies | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
Debt Security, Diverse Portfolio | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	57	126
Debt Security, Diverse Portfolio | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
Debt Security, Diverse Portfolio | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	57	126
Debt Security, Diverse Portfolio | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
US Government Agencies Debt Securities | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	81	102
US Government Agencies Debt Securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	68	82
US Government Agencies Debt Securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	13	20
US Government Agencies Debt Securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
Developed Markets, Government Agencies Debt Securities | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	10	19
Developed Markets, Government Agencies Debt Securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
Developed Markets, Government Agencies Debt Securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	10	19
Developed Markets, Government Agencies Debt Securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
Other | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	367	421
Other | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
Other | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
Other | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	367	421
Defined Benefit Plan, Real Estate, Hedge Funds, And Other [Member] | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	1,049	932
Defined Benefit Plan, Real Estate, Hedge Funds, And Other [Member] | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
Defined Benefit Plan, Real Estate, Hedge Funds, And Other [Member] | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	562	515
Defined Benefit Plan, Real Estate, Hedge Funds, And Other [Member] | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	$ 487	$ 417