XML 173 R116.htm IDEA: XBRL DOCUMENT v3.10.0.1
Investments in Debt and Equity Securities (Realized Gains and Losses) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
FV-NI:      
Realized gains $ 168    
Realized losses 126    
AFS:      
Realized gains 22    
Realized losses 51    
Available-for-sale Securities, Realized Gain (Loss) [Abstract]      
Realized gains   $ 202 $ 246
Realized losses   160 187
Duke Energy Carolinas [Member]      
FV-NI:      
Realized gains 89    
Realized losses 73    
AFS:      
Realized gains 19    
Realized losses 35    
Available-for-sale Securities, Realized Gain (Loss) [Abstract]      
Realized gains   135 157
Realized losses   103 121
Progress Energy [Member]      
FV-NI:      
Realized gains 79    
Realized losses 53    
AFS:      
Realized gains 3    
Realized losses 15    
Available-for-sale Securities, Realized Gain (Loss) [Abstract]      
Realized gains   65 84
Realized losses   56 64
Duke Energy Progress [Member]      
FV-NI:      
Realized gains 68    
Realized losses 48    
AFS:      
Realized gains 2    
Realized losses 10    
Available-for-sale Securities, Realized Gain (Loss) [Abstract]      
Realized gains   54 71
Realized losses   48 55
Duke Energy Florida [Member]      
FV-NI:      
Realized gains 11    
Realized losses 5    
AFS:      
Realized gains 1    
Realized losses $ 5    
Available-for-sale Securities, Realized Gain (Loss) [Abstract]      
Realized gains   11 13
Realized losses   $ 8 $ 9