Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	[1]	Sep. 30, 2017	Sep. 30, 2016	[1]
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 44,000,000	$ (26,000,000)		$ 2,344,000,000	$ (79,000,000)
De-recognition of deferred tax liabilities	$ 48,000,000			2,360,000,000
U.S. Federal Tax [Member] | REIT [Member]
Income Tax Disclosure [Abstract]
Provision for income taxes				$ 0

[1] Prior to the spin-off, we had one operating and reportable segment, our ownership segment. Prior period presentation has been restated to reflect our current reportable segment.