v3.20.2
Debt - Summary of Debt and Finance Leases (Detail) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended 12 Months Ended
Mar. 31, 2020
Sep. 30, 2020
Dec. 31, 2019
Debt Instrument [Line Items]      
Net Carrying Value, Current   $ 2,766 $ 1,399
Net Carrying Value, Long-Term   9,428 10,402
Unpaid Principal Balance   12,728 12,492
Unused Committed Amount   2,893 2,980
Net Carrying Value Finance leases, Current   360 386
Net Carrying Value Finance leases, Long-Term   1,131 1,232
Current portion of debt and finance leases   3,126 1,785
Debt and finance leases, net of current portion   10,559 11,634
5.30% Senior Notes due in 2025 ("2025 Notes") [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Long-Term   1,784 1,782
Solar asset-backed notes [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Long-Term   1,119 1,155
Solar Loan-backed Notes [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Long-Term   146 175
Recourse debt [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Current   1,636 253
Net Carrying Value, Long-Term   5,812 7,010
Unpaid Principal Balance   7,930 7,898
Unused Committed Amount   281 499
Recourse debt [Member] | 1.25% Convertible Senior Notes due in 2021 ("2021 Notes") [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Current   1,350  
Net Carrying Value, Long-Term     1,304
Unpaid Principal Balance   $ 1,376 $ 1,380
Contractual Interest Rates   1.25% 1.25%
Contractual Maturity Date 2021-03 2021-03 2021-03
Recourse debt [Member] | 2.375% Convertible Senior Notes due in 2022 [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Current   $ 249  
Net Carrying Value, Long-Term   678 $ 902
Unpaid Principal Balance   $ 977 $ 978
Contractual Interest Rates   2.375% 2.375%
Contractual Maturity Date   2022-03 2022-03
Recourse debt [Member] | 2.00% Convertible Senior Notes due in 2024 [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Current   $ 32  
Net Carrying Value, Long-Term   1,413 $ 1,383
Unpaid Principal Balance   $ 1,833 $ 1,840
Contractual Interest Rates   2.00% 2.00%
Contractual Maturity Date   2024-05 2024-05
Recourse debt [Member] | 5.30% Senior Notes due in 2025 ("2025 Notes") [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Long-Term   $ 1,784 $ 1,782
Unpaid Principal Balance   $ 1,800 $ 1,800
Contractual Interest Rates   5.30% 5.30%
Contractual Maturity Date   2025-08 2025-08
Recourse debt [Member] | Credit Agreement [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Current     $ 141
Net Carrying Value, Long-Term   $ 1,885 1,586
Unpaid Principal Balance   1,885 1,727
Unused Committed Amount   $ 281 $ 499
Contractual Interest Rates   3.30%  
Contractual Maturity Date   2023-07  
Contractual Maturity Date, Start     2020-06
Contractual Maturity Date, End     2023-07
Recourse debt [Member] | Credit Agreement [Member] | Minimum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates     2.70%
Recourse debt [Member] | Credit Agreement [Member] | Maximum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates     4.80%
Recourse debt [Member] | Zero-Coupon Convertible Senior Notes due in 2020 [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Current   $ 3 $ 97
Unpaid Principal Balance   $ 3 $ 103
Contractual Interest Rates   0.00% 0.00%
Contractual Maturity Date   2020-12 2020-12
Recourse debt [Member] | Solar Bonds and other Loans [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Current   $ 2 $ 15
Net Carrying Value, Long-Term   52 53
Unpaid Principal Balance   $ 56 $ 70
Contractual Maturity Date, Start   2020-10 2020-03
Contractual Maturity Date, End   2031-01 2031-01
Recourse debt [Member] | Solar Bonds and other Loans [Member] | Minimum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates   3.60% 3.60%
Recourse debt [Member] | Solar Bonds and other Loans [Member] | Maximum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates   5.80% 5.80%
Non-recourse debt [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Current   $ 1,130 $ 1,146
Net Carrying Value, Long-Term   3,616 3,392
Unpaid Principal Balance   4,798 4,594
Unused Committed Amount   2,612 2,481
Non-recourse debt [Member] | Warehouse Agreements [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Current   36 21
Net Carrying Value, Long-Term   267 146
Unpaid Principal Balance   303 167
Unused Committed Amount   $ 797 $ 933
Contractual Maturity Date   2022-09 2021-09
Non-recourse debt [Member] | Warehouse Agreements [Member] | Minimum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates   1.70% 3.10%
Non-recourse debt [Member] | Warehouse Agreements [Member] | Maximum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates   1.90% 3.60%
Non-recourse debt [Member] | China Loan Agreements [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Current     $ 444
Net Carrying Value, Long-Term   $ 592 297
Unpaid Principal Balance   592 741
Unused Committed Amount   $ 1,650 $ 1,542
Contractual Interest Rates   4.00%  
Contractual Maturity Date, Start   2020-12 2020-09
Contractual Maturity Date, End   2024-12 2024-12
Non-recourse debt [Member] | China Loan Agreements [Member] | Minimum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates     3.70%
Non-recourse debt [Member] | China Loan Agreements [Member] | Maximum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates     4.00%
Non-recourse debt [Member] | Automotive Lease-backed Credit Facilities [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Current   $ 17 $ 24
Net Carrying Value, Long-Term   18 16
Unpaid Principal Balance   35 $ 40
Unused Committed Amount   $ 144  
Contractual Maturity Date     2022-11
Contractual Maturity Date, Start   2022-09  
Contractual Maturity Date, End   2022-11  
Non-recourse debt [Member] | Automotive Lease-backed Credit Facilities [Member] | Minimum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates   1.90% 4.20%
Non-recourse debt [Member] | Automotive Lease-backed Credit Facilities [Member] | Maximum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates   5.90% 5.90%
Non-recourse debt [Member] | Solar Term Loans [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Current   $ 154 $ 8
Net Carrying Value, Long-Term     152
Unpaid Principal Balance   $ 155 $ 161
Contractual Interest Rates   3.70% 5.40%
Contractual Maturity Date   2021-01 2021-01
Non-recourse debt [Member] | Solar asset-backed notes [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Current   $ 40 $ 32
Net Carrying Value, Long-Term   1,079 1,123
Unpaid Principal Balance   $ 1,144 $ 1,183
Contractual Maturity Date, Start   2024-09 2024-09
Contractual Maturity Date, End   2048-02 2048-02
Non-recourse debt [Member] | Solar asset-backed notes [Member] | Minimum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates   3.00% 4.00%
Non-recourse debt [Member] | Solar asset-backed notes [Member] | Maximum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates   7.70% 7.70%
Non-recourse debt [Member] | Cash Equity Debt [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Current   $ 13 $ 10
Net Carrying Value, Long-Term   421 430
Unpaid Principal Balance   $ 447 $ 454
Contractual Maturity Date, Start   2033-07 2033-07
Contractual Maturity Date, End   2035-01 2035-01
Non-recourse debt [Member] | Cash Equity Debt [Member] | Minimum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates   5.30% 5.30%
Non-recourse debt [Member] | Cash Equity Debt [Member] | Maximum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates   5.80% 5.80%
Non-recourse debt [Member] | Automotive Asset-backed Notes [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Current   $ 857 $ 573
Net Carrying Value, Long-Term   1,027 997
Unpaid Principal Balance   $ 1,892 $ 1,577
Contractual Maturity Date, Start   2021-08 2020-02
Contractual Maturity Date, End   2024-08 2023-05
Non-recourse debt [Member] | Automotive Asset-backed Notes [Member] | Minimum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates   0.20% 2.00%
Non-recourse debt [Member] | Automotive Asset-backed Notes [Member] | Maximum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates   7.90% 7.90%
Non-recourse debt [Member] | Solar Loan-backed Notes [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Current   $ 13 $ 11
Net Carrying Value, Long-Term   133 164
Unpaid Principal Balance   $ 151 $ 182
Contractual Maturity Date, Start   2048-09 2048-09
Contractual Maturity Date, End   2049-09 2049-09
Non-recourse debt [Member] | Solar Loan-backed Notes [Member] | Minimum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates   4.80% 4.80%
Non-recourse debt [Member] | Solar Loan-backed Notes [Member] | Maximum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates   7.50% 7.50%
Non-recourse debt [Member] | Solar Renewable Energy Credit and other Loans [Member]      
Debt Instrument [Line Items]      
Net Carrying Value, Current     $ 23
Net Carrying Value, Long-Term   $ 79 67
Unpaid Principal Balance   79 89
Unused Committed Amount   $ 21 $ 6
Contractual Maturity Date, Start   2022-06 2020-03
Contractual Maturity Date, End   2033-02 2022-06
Non-recourse debt [Member] | Solar Renewable Energy Credit and other Loans [Member] | Minimum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates   2.70% 4.50%
Non-recourse debt [Member] | Solar Renewable Energy Credit and other Loans [Member] | Maximum [Member]      
Debt Instrument [Line Items]      
Contractual Interest Rates   5.10% 7.40%