Acquisitions and Dispositions (Schedule of Property Plant and Equipment) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Utility:
Generation	$ 19,250	$ 17,602
Transmission	16,669	15,335
Distribution	18,549	17,408
Storage	2,905	2,887
Nuclear fuel	1,626	1,599
General and other	1,476	1,514
Plant under construction	2,385	7,765
Total utility	64,930	66,049
Total property, plant and equipment	$ 76,578	$ 74,823
Generation
Utility:
Average composite depreciation rates on utility property, plant and equipment (percentage)	2.71%	2.94%	2.83%
Transmission
Utility:
Average composite depreciation rates on utility property, plant and equipment (percentage)	2.54%	2.55%	2.47%
Distribution
Utility:
Average composite depreciation rates on utility property, plant and equipment (percentage)	2.97%	3.00%	3.02%
Storage
Utility:
Average composite depreciation rates on utility property, plant and equipment (percentage)	2.40%	2.48%	2.29%
General and Other
Utility:
Average composite depreciation rates on utility property, plant and equipment (percentage)	4.56%	4.89%	4.12%
SCANA
Utility:
Generation	$ 5,720
Transmission	2,416
Distribution	6,044
Storage	99
Nuclear fuel	611
General and other	631
Plant under construction	527
Total utility	16,048
Nonutility, including plant under construction	283
Total property, plant and equipment	$ 16,331
SCANA | Generation
Utility:
Average composite depreciation rates on utility property, plant and equipment (percentage)	2.61%
SCANA | Transmission
Utility:
Average composite depreciation rates on utility property, plant and equipment (percentage)	2.47%
SCANA | Distribution
Utility:
Average composite depreciation rates on utility property, plant and equipment (percentage)	2.48%
SCANA | Storage
Utility:
Average composite depreciation rates on utility property, plant and equipment (percentage)	2.48%
SCANA | General and Other
Utility:
Average composite depreciation rates on utility property, plant and equipment (percentage)	5.64%