Loans - Wholesale Loan Portfolio - Impaired Loans (Details) - Wholesale - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Impaired loans
With an allowance	$ 1,035		$ 1,035		$ 1,070
Without an allowance	260		260		180
Total impaired loans	1,295		1,295		1,250
Allowance for loan losses related to impaired loans	288		288		297
Unpaid principal balance of impaired loans	1,488		1,488		1,723
Average impaired credit card loans	1,365	$ 1,546	1,466	$ 1,676
Troubled debt restructuring	462		462		576
Commercial and industrial
Impaired loans
With an allowance	734		734		807
Without an allowance	244		244		140
Total impaired loans	978		978		947
Allowance for loan losses related to impaired loans	209		209		252
Unpaid principal balance of impaired loans	1,131		1,131		1,043
Average impaired credit card loans	953	1,106	1,087	1,224
Real estate
Impaired loans
With an allowance	78		78		107
Without an allowance	14		14		27
Total impaired loans	92		92		134
Allowance for loan losses related to impaired loans	22		22		25
Unpaid principal balance of impaired loans	118		118		203
Average impaired credit card loans	106	142	118	142
Financial institutions
Impaired loans
With an allowance	10		10		4
Without an allowance	0		0		0
Total impaired loans	10		10		4
Allowance for loan losses related to impaired loans	2		2		1
Unpaid principal balance of impaired loans	11		11		4
Average impaired credit card loans	13	90	13	91
Governments & Agencies
Impaired loans
With an allowance	0		0		0
Without an allowance	0		0		0
Total impaired loans	0		0		0
Allowance for loan losses related to impaired loans	0		0		0
Unpaid principal balance of impaired loans	0		0		0
Average impaired credit card loans	0	0	0	0
Other
Impaired loans
With an allowance	213		213		152
Without an allowance	2		2		13
Total impaired loans	215		215		165
Allowance for loan losses related to impaired loans	55		55		19
Unpaid principal balance of impaired loans	228		228		$ 473
Average impaired credit card loans	$ 293	$ 208	$ 248	$ 219

The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.

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