Note 7 - Leases - Components of Lease Expense (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Depreciation of right-of-use assets		$ 17	$ 15
Interest on lease liabilities		8	7
Total finance lease expense		25	22
Operating lease expense		139	133
Variable lease expense		59	41
Short-term lease expense		2	4
Total lease expense		225	200
Principal	[1]	13	10
Interest	[1]	8	7
Total finance lease payments	[1]	21	17
Operating lease payments	[1]	134	121
Total lease payments	[1]	$ 155	$ 138

[1] Principle payments for finance leases have been classified as an investing outflow, and cash payments for operating leases, along with interest payments for finance leases, have been classified as an operating outflow on the consolidated statements of cash flows.