Note 12 - Fair Value Measurements and Derivatives - Fair Value of Financial Instruments (Details) - USD ($) $ in Millions		Jun. 30, 2020	Dec. 31, 2019
Reported Value Measurement [Member]
Long-term Debt		$ 2,837	$ 2,384
Reported Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Senior Notes [Member]
Long-term Debt		2,000	1,500
Reported Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Secured Debt [Member]
Long-term Debt		823	823
Reported Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Other Debt [Member]
Long-term Debt	[1]	14	61
Estimate of Fair Value Measurement [Member]
Long-term Debt		2,851	2,450
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Senior Notes [Member]
Long-term Debt		2,024	1,570
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Secured Debt [Member]
Long-term Debt		817	823
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Other Debt [Member]
Long-term Debt	[1]	$ 10	$ 57

[1] The carrying value includes the unamortized portion of a fair value adjustment related to a terminated interest rate swap at both dates.