Leases - Additional Information (Detail) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Operating Leased Assets [Line Items]
Lease revenue	$ 246	$ 485
Right of use lease assets	1,200	1,200
Lease liabilities	1,381	1,381
Lease cost	$ 100	$ 195
Minimum [Member] | Retail Leasing [Member]
Operating Leased Assets [Line Items]
Lease term		3 years
Maximum [Member] | Retail Leasing [Member]
Operating Leased Assets [Line Items]
Lease term		5 years