Employee Benefit Plans - Schedule of Pension Plan Assets at Fair Value (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	$ 8	$ 8	$ 12
Recurring
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	69	68
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	0	0
Recurring | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	61	60
Recurring | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	8	8
Recurring | Money market funds
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	1	1
Recurring | Money market funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	0	0
Recurring | Money market funds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	1	1
Recurring | Money market funds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	0	0
Recurring | Equity funds
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	23	22
Recurring | Equity funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	0	0
Recurring | Equity funds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	23	22
Recurring | Equity funds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	0	0
Recurring | Bond/fixed-income funds
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	30	35
Recurring | Bond/fixed-income funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	0	0
Recurring | Bond/fixed-income funds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	30	35
Recurring | Bond/fixed-income funds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	0	0
Recurring | Real estate indirect investments
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	7	2
Recurring | Real estate indirect investments | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	0	0
Recurring | Real estate indirect investments | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	7	2
Recurring | Real estate indirect investments | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	0	0
Recurring | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	8	8
Recurring | Insurance contracts | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	0	0
Recurring | Insurance contracts | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	0	0
Recurring | Insurance contracts | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	$ 8	$ 8