Leases - Assets and Liabilities of Lessee (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Jan. 01, 2019
Leases, Operating [Abstract]
Operating lease right-of-use assets	$ 589
Accounts payable and accrued liabilities	98
Operating lease liabilities	494	$ 502
Total operating lease liabilities	592
Finance leases
Property, plant and equipment, at cost	65
Accumulated depreciation	(19)
Property, plant and equipment, net	46
Current maturities of long-term debt and finance lease obligations	0
Long-term debt and finance lease obligations	53
Total finance lease liabilities	$ 53