Segment Disclosures (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment data
Net sales	$ 847	$ 1,038	$ 3,022	$ 3,541
Cost of sales	764	810	2,401	2,594
Gross margin	83	228	621	947
Total other operating costs and expenses	45	26	162	113
Equity in earnings (losses) of operating affiliate	2	(14)	8	(6)
Operating earnings	40	188	467	828
Ammonia
Segment data
Net sales	165	187	722	847
Granular Urea
Segment data
Net sales	249	327	915	1,103
UAN
Segment data
Net sales	248	309	791	934
AN
Segment data
Net sales	109	136	343	389
Operating Segments | Ammonia
Segment data
Net sales	165	187	722	847
Cost of sales	174	188	609	654
Gross margin	(9)	(1)	113	193
Operating Segments | Granular Urea
Segment data
Net sales	249	327	915	1,103
Cost of sales	183	207	612	686
Gross margin	66	120	303	417
Operating Segments | UAN
Segment data
Net sales	248	309	791	934
Cost of sales	237	250	675	722
Gross margin	11	59	116	212
Operating Segments | AN
Segment data
Net sales	109	136	343	389
Cost of sales	96	100	290	308
Gross margin	13	36	53	81
Operating Segments | Other
Segment data
Net sales	76	79	251	268
Cost of sales	74	65	215	224
Gross margin	$ 2	$ 14	$ 36	$ 44