Variable Interest Entities - Unconsolidated VIEs (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Unconsolidated Assets
Interest Bearing Deposits in Banks	$ 1,846		$ 3,844
Securities Available for Sale	18,114		14,141
Other Assets	8,454		8,496
Unconsolidated Liabilities
Other Liabilities	2,834		2,520
Unconsolidated VIEs
Unconsolidated Assets
Interest Bearing Deposits in Banks	1		1
Securities Available for Sale	29		37
Loans Held for Investment	272		239
Other Assets	2,688		2,941
Total Assets	2,990		3,218
Unconsolidated Liabilities
Other Liabilities	348		447
Total Liabilities	348		447
Maximum Exposure to Loss	3,055		3,271
Unconsolidated VIEs | LIHC investments
Variable Interest Entities
Liabilities Assumed	22	$ 47
Unconsolidated Assets
Interest Bearing Deposits in Banks	0		0
Securities Available for Sale	29		25
Loans Held for Investment	222		168
Other Assets	1,076		1,164
Total Assets	1,327		1,357
Unconsolidated Liabilities
Other Liabilities	281		381
Total Liabilities	281		381
Maximum Exposure to Loss	1,327		1,357
Unconsolidated VIEs | Leasing investments
Unconsolidated Assets
Interest Bearing Deposits in Banks	1		1
Securities Available for Sale	0		12
Loans Held for Investment	26		47
Other Assets	1,588		1,751
Total Assets	1,615		1,811
Unconsolidated Liabilities
Other Liabilities	67		66
Total Liabilities	67		66
Maximum Exposure to Loss	1,637		1,833
Unconsolidated VIEs | Other investments
Unconsolidated Assets
Interest Bearing Deposits in Banks	0		0
Securities Available for Sale	0		0
Loans Held for Investment	24		24
Other Assets	24		26
Total Assets	48		50
Unconsolidated Liabilities
Other Liabilities	0		0
Total Liabilities	0		0
Maximum Exposure to Loss	$ 91		$ 81