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		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement		$ 300,171		$ 300,171		$ 299,181
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement		2,227		2,227		2,476
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement		86	$ 74	183	$ 155
Commercial Portfolio Segment [Member]
Principal Amount Outstanding of Loans Held-in-portfolio		83,991		83,991		80,940
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement		274		274		175
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement		16	17	44	34
Consumer Portfolio Segment [Member]
Principal Amount Outstanding of Loans Held-in-portfolio		72,598		72,598		70,899
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement		1,738		1,738		2,003
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement		69	56	138	118
Loans and Finance Receivables [Member]
Principal Amount Outstanding of Loans Held-in-portfolio		156,589		156,589		151,839
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement		2,012		2,012		2,178
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement		85	73	182	152
Asset-backed Securities, Securitized Loans and Receivables [Member]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement		143,021		143,021		146,208
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement		148		148		146
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement		1	1	1	3
Loans [Member]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	[1]	561		561		1,134
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	[1]	67		67		152
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement		0	0	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]	6,732		6,732		6,399
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	[2]	0		0		0
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement		0	0	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		136,289		136,289		139,809
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement		148		148		$ 146
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	[3]	$ 1	$ 1	$ 1	$ 3

[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 $308 million and $387 million of managed securitized loans at June 30, 2019 and December 31, 2018, respectively. Net charge-off data is not reported to the Company for the remaining balance of $136.0 billion and $139.4 billion of managed securitized loans at June 30, 2019 and December 31, 2018, respectively.