Leases - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) contract
Lower Limit
Operating Leased Assets [Line Items]
Number of lease renewal options | contract	1
Renewal option period	5 years
Upper Limit
Operating Leased Assets [Line Items]
Leases, initial terms	20 years
Renewal option period	10 years
Primary Obligations Operating Leases
Operating Leased Assets [Line Items]
Obligations of consolidated subsidiaries	$ 962
Consolidated Subsidiaries Non Recourse to Parent | Primary Obligations Operating Leases
Operating Leased Assets [Line Items]
Obligations of consolidated subsidiaries	$ 186