Leases - Maturities (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Leases
Operating lease cost	$ 132	$ 129	$ 134
Finance lease cost	48
Operating
2020	63
2021	58
2022	57
2023	51
2024	40
Thereafter	359
Total lease payments	628
Less: interest	(183)
Discounted lease liabilities	445
Operating leases not yet commenced	$ 26
Operating leases not yet commenced term	15 years
Financing
2020	$ 47
2021	45
2022	45
2023	44
2024	41
Thereafter	256
Total lease payments	478
Less: interest	(119)
Discounted lease liabilities	$ 359