Financing Receivables, Receivables Purchased/Participated from IBM - Credit Quality Indicators (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Troubled debt restructurings of financing receivables
Lease receivables | Americas
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		3,133
Lease receivables | Americas | Aaa - Aa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		305
Lease receivables | Americas | A1 - A3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		700
Lease receivables | Americas | Baa1 - Baa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		949
Lease receivables | Americas | Ba1 - Ba2
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		733
Lease receivables | Americas | Ba3 - B1
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		196
Lease receivables | Americas | B2 - B3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		236
Lease receivables | Americas | Caa - D
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		13
Lease receivables | EMEA
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		689
Lease receivables | EMEA | Aaa - Aa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		55
Lease receivables | EMEA | A1 - A3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		88
Lease receivables | EMEA | Baa1 - Baa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		153
Lease receivables | EMEA | Ba1 - Ba2
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		206
Lease receivables | EMEA | Ba3 - B1
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		137
Lease receivables | EMEA | B2 - B3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		45
Lease receivables | EMEA | Caa - D
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		5
Lease receivables | Asia Pacific
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		396
Lease receivables | Asia Pacific | Aaa - Aa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		31
Lease receivables | Asia Pacific | A1 - A3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		124
Lease receivables | Asia Pacific | Baa1 - Baa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		83
Lease receivables | Asia Pacific | Ba1 - Ba2
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		61
Lease receivables | Asia Pacific | Ba3 - B1
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		62
Lease receivables | Asia Pacific | B2 - B3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		32
Lease receivables | Asia Pacific | Caa - D
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		2
Loan receivables | Americas
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		6,105
Loan receivables | Americas | Aaa - Aa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		732
Loan receivables | Americas | A1 - A3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		1,166
Loan receivables | Americas | Baa1 - Baa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		1,756
Loan receivables | Americas | Ba1 - Ba2
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		1,461
Loan receivables | Americas | Ba3 - B1
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		444
Loan receivables | Americas | B2 - B3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		513
Loan receivables | Americas | Caa - D
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		32
Loan receivables | EMEA
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		2,403
Loan receivables | EMEA | Aaa - Aa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		89
Loan receivables | EMEA | A1 - A3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		178
Loan receivables | EMEA | Baa1 - Baa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		907
Loan receivables | EMEA | Ba1 - Ba2
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		532
Loan receivables | EMEA | Ba3 - B1
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		455
Loan receivables | EMEA | B2 - B3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		228
Loan receivables | EMEA | Caa - D
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		15
Loan receivables | Asia Pacific
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		674
Loan receivables | Asia Pacific | Aaa - Aa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		89
Loan receivables | Asia Pacific | A1 - A3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		237
Loan receivables | Asia Pacific | Baa1 - Baa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		107
Loan receivables | Asia Pacific | Ba1 - Ba2
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		159
Loan receivables | Asia Pacific | Ba3 - B1
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		46
Loan receivables | Asia Pacific | B2 - B3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		33
Loan receivables | Asia Pacific | Caa - D
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		3
Long-term participated receivables from IBM | Americas
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		714
Long-term participated receivables from IBM | Americas | Aaa - Aa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		440
Long-term participated receivables from IBM | Americas | A1 - A3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		71
Long-term participated receivables from IBM | Americas | Baa1 - Baa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		104
Long-term participated receivables from IBM | Americas | Ba1 - Ba2
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		49
Long-term participated receivables from IBM | Americas | Ba3 - B1
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		43
Long-term participated receivables from IBM | Americas | B2 - B3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		4
Long-term participated receivables from IBM | Americas | Caa - D
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		2
Long-term participated receivables from IBM | EMEA
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		1,668
Long-term participated receivables from IBM | EMEA | Aaa - Aa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		88
Long-term participated receivables from IBM | EMEA | A1 - A3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		271
Long-term participated receivables from IBM | EMEA | Baa1 - Baa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		762
Long-term participated receivables from IBM | EMEA | Ba1 - Ba2
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		442
Long-term participated receivables from IBM | EMEA | Ba3 - B1
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		88
Long-term participated receivables from IBM | EMEA | B2 - B3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		18
Long-term participated receivables from IBM | EMEA | Caa - D
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		0
Long-term participated receivables from IBM | Asia Pacific
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		1,921
Long-term participated receivables from IBM | Asia Pacific | Aaa - Aa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		89
Long-term participated receivables from IBM | Asia Pacific | A1 - A3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		934
Long-term participated receivables from IBM | Asia Pacific | Baa1 - Baa3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		500
Long-term participated receivables from IBM | Asia Pacific | Ba1 - Ba2
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		245
Long-term participated receivables from IBM | Asia Pacific | Ba3 - B1
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		126
Long-term participated receivables from IBM | Asia Pacific | B2 - B3
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		26
Long-term participated receivables from IBM | Asia Pacific | Caa - D
Amortized cost/recorded investment for each class of receivables, by credit quality indicator
Financing receivables, net recorded investment		$ 2