Organization and Basis of Presentation (Schedule of Cash and Cash Equivalents) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Current Assets
Cash and cash equivalents	$ 377	$ 442
Other	134	141
Other Noncurrent Assets
Other	39	8
Total cash, cash equivalents and restricted cash	550	591	$ 579	$ 505
Progress Energy [Member]
Current Assets
Cash and cash equivalents	45	67
Other	12	39
Other Noncurrent Assets
Other	38	6
Total cash, cash equivalents and restricted cash	95	112	39	87
Duke Energy Florida [Member]
Current Assets
Cash and cash equivalents	8	36
Other	12	39
Other Noncurrent Assets
Total cash, cash equivalents and restricted cash	$ 20	$ 75	$ 19	$ 53