Intangible Assets - Schedule of Other Intangible Assets (Parenthetical) (Detail) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)
Finite Lived Intangible Assets [Line Items]
Other intangibles amortization	$ 10	$ 10
Other Intangible Assets [Member]
Finite Lived Intangible Assets [Line Items]
Other intangibles amortization	10
Amortization expense for intangible assets, remainder of 2018	45	45
Amortization expense for intangible assets, in 2019	81	81
Amortization expense for intangible assets, in 2020	81	81
Amortization expense for intangible assets, in 2021	77	77
Amortization expense for intangible assets, in 2022	$ 73	$ 73