Organization and Basis of Presentation (Schedule of Cash and Cash Equivalents) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Current Assets
Cash and cash equivalents	$ 379	$ 442
Other	163	141
Other Noncurrent Assets
Other	40	8
Total cash, cash equivalents and restricted cash	582	591	$ 449	$ 505
Progress Energy [Member]
Current Assets
Cash and cash equivalents	82	67
Other	16	39
Other Noncurrent Assets
Other	38	6
Total cash, cash equivalents and restricted cash	136	112	63	87
Duke Energy Florida [Member]
Current Assets
Cash and cash equivalents	24	36
Other	16	39
Other Noncurrent Assets
Total cash, cash equivalents and restricted cash	$ 40	$ 75	$ 34	$ 53