Summary of Significant Accounting Policies (Schedule of Cash and Cash Equivalents) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current Assets
Cash and cash equivalents	$ 311	$ 442
Other	222	141
Other Noncurrent Assets
Other	40	8
Total cash, cash equivalents and restricted cash	573	591	$ 505	$ 541
Progress Energy
Current Assets
Cash and cash equivalents	48	67
Other	39	39
Other Noncurrent Assets
Other	39	6
Total cash, cash equivalents and restricted cash	126	112	87	110
Duke Energy Florida
Current Assets
Cash and cash equivalents	17	36
Other	39	39
Other Noncurrent Assets
Other	0	0
Total cash, cash equivalents and restricted cash	$ 56	$ 75	$ 53	$ 69