Leases - Reconciliation of Total Lease Payments, on Undiscounted Basis, to Lease Liability in Statement of Financial Position (Detail) $ in Millions	Dec. 31, 2019 USD ($)
Lessee Lease Description [Line Items]
Weighted-average discount rate - operating leases	5.30%
2020	$ 39
2021	38
2022	38
2023	36
2024	36
Thereafter	1,586
Total undiscounted cash flows	1,773
Long-term lease liabilities	606
Lease liabilities	606
Difference between undiscounted cash flows and discounted cash flows	$ 1,167
Ground Leases
Lessee Lease Description [Line Items]
Weighted-average discount rate - operating leases	5.40%
2020	$ 32
2021	32
2022	32
2023	32
2024	32
Thereafter	1,530
Total undiscounted cash flows	1,690
Long-term lease liabilities	543
Lease liabilities	543
Difference between undiscounted cash flows and discounted cash flows	$ 1,147
Office Leases and Other
Lessee Lease Description [Line Items]
Weighted-average discount rate - operating leases	3.60%
2020	$ 7
2021	6
2022	6
2023	4
2024	4
Thereafter	56
Total undiscounted cash flows	83
Long-term lease liabilities	63
Lease liabilities	63
Difference between undiscounted cash flows and discounted cash flows	$ 20