Segments Of Business (Tables)

12 Months Ended

Dec. 31, 2020

Segment Reporting Information [Line Items]

Schedule of Segments of Business

Certain financial information relating to Alliant Energy’s business segments, which represent the services provided to its customers, was as follows (in millions):

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2020	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$2,920	$373	$49	$3,342	$74	$3,416
Depreciation and amortization	556	49	5	610	5	615
Operating income (loss)	643	74	(1)	716	24	740
Interest expense				243	32	275
Equity income from unconsolidated investments, net	(2)	—	—	(2)	(59)	(61)
Income tax expense (benefit)				(66)	9	(57)
Net income attributable to Alliant Energy common shareowners				573	41	614
Total assets	14,358	1,413	990	16,761	949	17,710
Investments in equity method subsidiaries	11	—	—	11	465	476
Construction and acquisition expenditures	1,109	182	2	1,293	73	1,366

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2019	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$3,064	$455	$46	$3,565	$83	$3,648
Depreciation and amortization	513	47	3	563	4	567
Operating income	679	70	1	750	28	778
Interest expense				229	44	273
Equity income from unconsolidated investments, net	(1)	—	—	(1)	(52)	(53)
Income tax expense (benefit)				73	(4)	69
Net income attributable to Alliant Energy common shareowners				517	40	557
Total assets	13,659	1,269	856	15,784	917	16,701
Investments in equity method subsidiaries	9	—	—	9	449	458
Construction and acquisition expenditures	1,439	100	—	1,539	101	1,640

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2018	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$3,000	$447	$48	$3,495	$39	$3,534
Depreciation and amortization	457	42	3	502	5	507
Operating income	610	53	1	664	30	694
Interest expense				217	30	247
Equity income from unconsolidated investments, net	(1)	—	—	(1)	(54)	(55)
Income taxes				33	15	48
Net income attributable to Alliant Energy common shareowners				472	40	512
Total assets	12,486	1,184	893	14,563	863	15,426
Investments in equity method subsidiaries	8	—	—	8	413	421
Construction and acquisition expenditures	1,422	147	—	1,569	65	1,634

IPL [Member]

Segment Reporting Information [Line Items]

Schedule of Segments of Business

Certain financial information relating to IPL’s business segments, which represent the services provided to its customers, was as follows (in millions):

2020	Electric	Gas	Other	Total
Revenues	$1,695	$208	$44	$1,947
Depreciation and amortization	321	30	5	356
Operating income	358	50	2	410
Interest expense				139
Income tax benefit				(47)
Net income available for common stock				324
Total assets	8,518	766	565	9,849
Construction and acquisition expenditures	626	59	2	687

2019	Electric	Gas	Other	Total
Revenues	$1,781	$264	$44	$2,089
Depreciation and amortization	295	29	3	327
Operating income	360	39	4	403
Interest expense				127
Income taxes				24
Net income available for common stock				284
Total assets	8,075	734	468	9,277
Construction and acquisition expenditures	964	56	—	1,020

2018	Electric	Gas	Other	Total
Revenues	$1,731	$266	$45	$2,042
Depreciation and amortization	255	25	3	283
Operating income	318	28	5	351
Interest expense				119
Income tax benefit				(3)
Net income available for common stock				264
Total assets	7,220	687	504	8,411
Construction and acquisition expenditures	891	100	—	991

WPL [Member]

Segment Reporting Information [Line Items]

Schedule of Segments of Business

Certain financial information relating to WPL’s business segments, which represent the services provided to its customers, was as follows (in millions):

2020	Electric	Gas	Other	Total
Revenues	$1,225	$165	$5	$1,395
Depreciation and amortization	235	19	—	254
Operating income (loss)	285	24	(3)	306
Interest expense				104
Income tax benefit				(19)
Net income				249
Total assets	5,840	647	425	6,912
Construction and acquisition expenditures	483	123	—	606

2019	Electric	Gas	Other	Total
Revenues	$1,283	$191	$2	$1,476
Depreciation and amortization	218	18	—	236
Operating income (loss)	319	31	(3)	347
Interest expense				102
Income taxes				49
Net income				233
Total assets	5,584	535	388	6,507
Construction and acquisition expenditures	475	44	—	519

2018	Electric	Gas	Other	Total
Revenues	$1,269	$181	$3	$1,453
Depreciation and amortization	202	17	—	219
Operating income (loss)	292	25	(4)	313
Interest expense				98
Income taxes				36
Net income				208
Total assets	5,266	497	389	6,152
Construction and acquisition expenditures	531	47	—	578