Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Allowance for doubtful accounts - receivables	$ 17	$ 14
Regulatory assets, current	1,906	1,437
Other, current assets	1,092	634
Regulatory assets, noncurrent	12,616	12,442
Current maturities of long-term debt	3,455	3,244
Long-Term Debt	$ 50,507	$ 49,035
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, shares outstanding	713,000,000	700,000,000
Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	$ 55	$ 54
Regulatory assets, current	52	51
Regulatory assets, noncurrent	1,055	1,091
Current maturities of long-term debt	228	225
Long-Term Debt	4,015	4,306
Duke Energy Carolinas [Member]
Allowance for doubtful accounts - receivables	2	2
Regulatory assets, current	435	299
Other, current assets	55	19
Regulatory assets, noncurrent	3,188	2,853
Current maturities of long-term debt	506	1,205
Long-Term Debt	9,589	8,598
Duke Energy Carolinas [Member] | Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	7	7
Progress Energy [Member]
Allowance for doubtful accounts - receivables	5	4
Regulatory assets, current	1,122	741
Other, current assets	256	334
Regulatory assets, noncurrent	5,987	6,010
Current maturities of long-term debt	1,322	771
Long-Term Debt	$ 17,440	$ 16,916
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100	100
Common stock, shares outstanding	100	100
Progress Energy [Member] | Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	$ 8	$ 7
Regulatory assets, current	52	51
Regulatory assets, noncurrent	1,055	1,091
Current maturities of long-term debt	53	53
Long-Term Debt	1,636	1,689
Duke Energy Progress [Member]
Allowance for doubtful accounts - receivables	2	1
Regulatory assets, current	677	352
Other, current assets	112	97
Regulatory assets, noncurrent	3,822	3,507
Current maturities of long-term debt	603	3
Long-Term Debt	7,401	7,204
Duke Energy Progress [Member] | Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	5	5
Duke Energy Florida [Member]
Allowance for doubtful accounts - receivables	3	3
Regulatory assets, current	445	389
Other, current assets	27	86
Regulatory assets, noncurrent	2,165	2,503
Current maturities of long-term debt	269	768
Long-Term Debt	7,102	6,327
Duke Energy Florida [Member] | Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	3	2
Regulatory assets, current	52	51
Other, current assets	14	40
Regulatory assets, noncurrent	1,055	1,091
Current maturities of long-term debt	53	53
Long-Term Debt	1,336	1,389
Duke Energy Ohio [Member]
Allowance for doubtful accounts - receivables	3	3
Regulatory assets, current	41	49
Other, current assets	28	39
Regulatory assets, noncurrent	427	445
Current maturities of long-term debt	452	3
Long-Term Debt	$ 1,589	$ 2,039
Common stock, par value	$ 8.50	$ 8.50
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares outstanding	90,000,000	90,000,000
Duke Energy Indiana [Member]
Allowance for doubtful accounts - receivables	$ 2	$ 2
Regulatory assets, current	190	165
Other, current assets	64	30
Regulatory assets, noncurrent	950	978
Current maturities of long-term debt	62	3
Long-Term Debt	3,571	3,630
Piedmont Natural Gas [Member]
Allowance for doubtful accounts - receivables	1	2
Regulatory assets, current	38	95
Other, current assets	48	52
Regulatory assets, noncurrent	305	283
Current maturities of long-term debt	350	250
Long-Term Debt	$ 1,788	$ 1,787
Common stock, shares authorized	100	100
Common stock, shares outstanding	100	100