Lease Obligations - Lessee (Undiscounted Cash Flows) (Detail) $ in Millions	Mar. 31, 2019 USD ($)
Operating Leases
Remainder of 2019	$ 75
2020	88
2021	75
2022	67
2023	59
2024	51
Thereafter	225
Total undiscounted cash flows	640
Less: Difference between undiscounted cash flows and discounted cash flows	(95)
Operating lease liabilities	545
Finance Leases
Remainder of 2019	4
2020	5
2021	4
2022	4
2023	0
2024	0
Thereafter	2
Total undiscounted cash flows	19
Less: Difference between undiscounted cash flows and discounted cash flows	(2)
Finance lease liabilities	17
Total
Remainder of 2019	79
2020	93
2021	79
2022	71
2023	59
2024	51
Thereafter	227
Total undiscounted cash flows	659
Less: Difference between undiscounted cash flows and discounted cash flows	(97)
Total lease liabilities	$ 562