XML 101 R92.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Leases (Narrative) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Lessee, Lease, Description [Line Items]      
Operating lease assets, cost basis $ 147,654 $ 134,458  
Piedmont      
Lessee, Lease, Description [Line Items]      
Operating lease assets, cost basis 8,446 7,486  
Construction and transportation of natural gas pipelines | Piedmont      
Lessee, Lease, Description [Line Items]      
Net Investment in Lease, Current 4    
Renewable energy projects      
Lessee, Lease, Description [Line Items]      
Contingent lease payments 264 268 $ 262
Operating lease assets, cost basis 3,349 3,358  
Operating lease assets, accumulated depreciation 721 $ 602  
Duke Energy Carolinas | Construction and transportation of natural gas pipelines | Piedmont      
Lessee, Lease, Description [Line Items]      
Net Investment in Lease, Noncurrent $ 70