v3.20.2
Summary of Significant Accounting Policies - Schedule of Disaggregation of Revenue by Major Source (Detail) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Disaggregation Of Revenue [Line Items]        
Leasing revenues $ 265 $ 221 $ 772 $ 644
Total revenues 8,771 6,303 20,792 17,194
Services and Other [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenues from sales and services 581 548 1,628 1,646
Sales and Services [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenues from sales and services 8,366 5,921 19,615 16,135
Automotive [Member] | Automotive Sales without Resale Value Guarantee [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenues from sales and services 6,788 4,821 15,578 13,423
Automotive [Member] | Automotive Sales with Resale Value Guarantee [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenues from sales and services 161 177 393 (75)
Automotive [Member] | Automotive Regulatory Credits [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenues from sales and services 397 134 1,179 461
Automotive [Member] | Automotive Leasing [Member]        
Disaggregation Of Revenue [Line Items]        
Leasing revenues 265 221 772 644
Energy Generation and Storage [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenues 579 402 1,242 1,095
Energy Generation and Storage [Member] | Energy Generation and Storage Sales [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenues from sales and services 439 241 837 680
Energy Generation and Storage [Member] | Energy Generation and Storage Leasing [Member]        
Disaggregation Of Revenue [Line Items]        
Leasing revenues $ 140 $ 161 $ 405 $ 415