Portfolio Balances and Delinquency Balances Based on 90 days or more Past Due and Net Charge-Offs Related to Managed Portfolio Loans (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement		$ 300,724		$ 299,181
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement		2,408		2,476
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement		97	$ 81
Commercial Portfolio Segment [Member]
Principal Amount Outstanding of Loans Held-in-portfolio		83,729		80,940
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement		215		175
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement		28	17
Consumer Portfolio Segment [Member]
Principal Amount Outstanding of Loans Held-in-portfolio		71,504		70,899
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement		1,966		2,003
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement		69	62
Loans and Finance Receivables [Member]
Principal Amount Outstanding of Loans Held-in-portfolio		155,233		151,839
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement		2,181		2,178
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement		97	79
Asset-backed Securities, Securitized Loans and Receivables [Member]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement		144,884		146,208
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement		148		146
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement		0	2
Loans [Member]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	[1]	607		1,134
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	[1]	79		152
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement		0	0
Commercial Portfolio Segment [Member] | Asset-backed Securities, Securitized Loans and Receivables [Member]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	[2]	6,585		6,399
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	[2]	0		0
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement		0	0
Consumer Portfolio Segment [Member] | Asset-backed Securities, Securitized Loans and Receivables [Member]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement		138,299		139,809
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement		148		$ 146
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	[3]	$ 0	$ 2

[1] Comprised of unsecuritized loans the Company originated and sold to private investors with servicing rights retained. Net charge-offs on these loans are not presented in the table as the data is not reported to the Company by the private investors that own these related loans.

[2] Comprised of commercial mortgages sold through Fannie Mae, Freddie Mac, and Ginnie Mae securitizations, whereby servicing has been retained by the Company.

[3] Amounts associated with $347 million and $387 million of managed securitized loans at March 31, 2019 and December 31, 2018, respectively. Net charge-off data is not reported to the Company for the remaining balance of $138.0 billion and $139.4 billion of managed securitized loans at March 31, 2019 and December 31, 2018, respectively.