Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Allowance for doubtful accounts - receivables	$ 14	$ 14
Regulatory assets	1,437	1,023
Regulatory assets, noncurrent	12,442	12,878
Other	634	458
Current maturities of long-term debt	3,244	2,319
Long-Term Debt	$ 49,035	$ 45,576
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, shares outstanding	700,000,000	700,000,000
Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	$ 54	$ 54
Regulatory assets	51	50
Regulatory assets, noncurrent	1,091	1,142
Current maturities of long-term debt	225	260
Long-Term Debt	4,306	3,587
Duke Energy Carolinas [Member]
Allowance for doubtful accounts - receivables	2	2
Regulatory assets	299	238
Regulatory assets, noncurrent	2,853	3,159
Other	19	37
Current maturities of long-term debt	1,205	116
Long-Term Debt	8,598	9,187
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	4	6
Regulatory assets	741	401
Regulatory assets, noncurrent	6,010	5,722
Other	334	148
Current maturities of long-term debt	771	778
Long-Term Debt	$ 16,916	$ 15,590
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	$ 7	$ 7
Regulatory assets	51	50
Regulatory assets, noncurrent	1,091	1,142
Current maturities of long-term debt	53	62
Long-Term Debt	1,689	1,741
Duke Energy Progress [Member]
Allowance for doubtful accounts - receivables	1	4
Regulatory assets	352	188
Regulatory assets, noncurrent	3,507	3,243
Other	97	57
Current maturities of long-term debt	3	452
Long-Term Debt	7,204	6,409
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	2
Regulatory assets	389	213
Regulatory assets, noncurrent	2,503	2,480
Other	86	125
Current maturities of long-term debt	768	326
Long-Term Debt	6,327	5,799
Duke Energy Florida [Member] | Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	2	2
Regulatory assets	51	50
Regulatory assets, noncurrent	1,091	1,142
Other	40	53
Current maturities of long-term debt	53	62
Long-Term Debt	1,389	1,442
Duke Energy Ohio [Member]
Allowance for doubtful accounts - receivables	3	2
Regulatory assets	49	37
Regulatory assets, noncurrent	445	520
Other	39	37
Current maturities of long-term debt	3	1
Long-Term Debt	$ 2,039	$ 1,858
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	$ 1
Regulatory assets	165	149
Regulatory assets, noncurrent	978	1,073
Other	30	45
Current maturities of long-term debt	3	3
Long-Term Debt	3,630	3,633
Piedmont Natural Gas [Member]
Allowance for doubtful accounts - receivables	2	3
Regulatory assets	95	124
Regulatory assets, noncurrent	283	373
Other	52	21
Current maturities of long-term debt	250	35
Long-Term Debt	$ 1,787	$ 1,786
Common stock, shares authorized	100	100
Common stock, shares outstanding	100	100