Note 2 - Revenue Recognition - Disaggregated Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Sales	$ 742	$ 609
Gas Utilities [Member]
Sales	271	210
Downstream [Member]
Sales	226	194
Upstream [Member]
Sales	158	127
Midstream [Member]
Sales	87	78
UNITED STATES
Sales	618	484
UNITED STATES | Gas Utilities [Member]
Sales	268	209
UNITED STATES | Downstream [Member]
Sales	169	138
UNITED STATES | Upstream [Member]
Sales	101	68
UNITED STATES | Midstream [Member]
Sales	80	69
CANADA
Sales	43	32
CANADA | Gas Utilities [Member]
Sales	3	1
CANADA | Downstream [Member]
Sales	7	4
CANADA | Upstream [Member]
Sales	29	23
CANADA | Midstream [Member]
Sales	4	4
International [Member]
Sales	81	93
International [Member] | Gas Utilities [Member]
Sales	0	0
International [Member] | Downstream [Member]
Sales	50	52
International [Member] | Upstream [Member]
Sales	28	36
International [Member] | Midstream [Member]
Sales	$ 3	$ 5