Fair Value Measurements (Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Assets
Investment securities available-for-sale	$ 1,614	$ 1,480
Investment securities held-to-maturity	1,008	1,084
Loans held-for-sale	4,473	3,145
Loans held-for-investment	13	72
Mortgage servicing rights	184	335
Carrying Value
Assets
Cash and cash equivalents	183	158
Investment securities available-for-sale	1,614	1,480
Investment securities held-to-maturity	1,014	1,093
Loans held-for-sale	4,506	3,177
Loans held-for-investment	6,776	6,065
Loans with government guarantees	278	365
Mortgage servicing rights	184	335
Federal Home Loan Bank stock	260	180
Bank owned life insurance	325	271
Repossessed assets	9	14
Other assets, foreclosure claims	99	135
Derivative financial instruments, assets	68	123
Liabilities
Federal Home Loan Bank advances	(4,870)	(2,980)
Long-term debt	(493)	(493)
Warrant liabilities		(4)
DOJ litigation settlement	(60)	(60)
Contingent consideration	(23)
Derivative financial instruments, liabilities	(8)	(54)
Carrying Value | Demand deposits and savings accounts
Liabilities
Deposits	(5,394)	(5,268)
Carrying Value | Certificates of deposit
Liabilities
Deposits	(1,153)	(1,056)
Carrying Value | Government deposits
Liabilities
Deposits	(851)	(1,030)
Carrying Value | Company controlled deposits
Liabilities
Deposits	(1,297)	(1,446)
Estimated Fair Value
Assets
Cash and cash equivalents	183	158
Investment securities available-for-sale	1,614	1,480
Investment securities held-to-maturity	1,008	1,084
Loans held-for-sale	4,674	3,178
Loans held-for-investment	6,867	5,998
Loans with government guarantees	269	354
Mortgage servicing rights	184	335
Federal Home Loan Bank stock	260	180
Bank owned life insurance	325	271
Repossessed assets	9	14
Other assets, foreclosure claims	99	135
Derivative financial instruments, assets	68	123
Liabilities
Federal Home Loan Bank advances	(4,856)	(2,964)
Long-term debt	(382)	(277)
Warrant liabilities		(4)
DOJ litigation settlement	(60)	(60)
Contingent consideration	(23)
Derivative financial instruments, liabilities	(8)	(54)
Estimated Fair Value | Demand deposits and savings accounts
Liabilities
Deposits	(4,998)	(4,956)
Estimated Fair Value | Certificates of deposit
Liabilities
Deposits	(1,159)	(1,062)
Estimated Fair Value | Government deposits
Liabilities
Deposits	(834)	(1,011)
Estimated Fair Value | Company controlled deposits
Liabilities
Deposits	(994)	(1,371)
Estimated Fair Value | Level 1
Assets
Cash and cash equivalents	183	158
Investment securities available-for-sale	0	0
Investment securities held-to-maturity	0	0
Loans held-for-sale	0	0
Loans held-for-investment	0	0
Loans with government guarantees	0	0
Mortgage servicing rights	0	0
Federal Home Loan Bank stock	0	0
Bank owned life insurance	0	0
Repossessed assets	0	0
Other assets, foreclosure claims	0	0
Derivative financial instruments, assets	0	45
Liabilities
Federal Home Loan Bank advances	0	0
Long-term debt	0	0
Warrant liabilities		0
DOJ litigation settlement	0	0
Contingent consideration	0
Derivative financial instruments, liabilities	(1)	(11)
Estimated Fair Value | Level 1 | Demand deposits and savings accounts
Liabilities
Deposits	0	0
Estimated Fair Value | Level 1 | Certificates of deposit
Liabilities
Deposits	0	0
Estimated Fair Value | Level 1 | Government deposits
Liabilities
Deposits	0	0
Estimated Fair Value | Level 1 | Company controlled deposits
Liabilities
Deposits	0	0
Estimated Fair Value | Level 2
Assets
Cash and cash equivalents	0	0
Investment securities available-for-sale	1,614	1,480
Investment securities held-to-maturity	1,008	1,084
Loans held-for-sale	4,674	3,178
Loans held-for-investment	8	7
Loans with government guarantees	269	354
Mortgage servicing rights	0	0
Federal Home Loan Bank stock	260	180
Bank owned life insurance	325	271
Repossessed assets	0	0
Other assets, foreclosure claims	99	135
Derivative financial instruments, assets	41	54
Liabilities
Federal Home Loan Bank advances	(4,856)	(2,964)
Long-term debt	(382)	(277)
Warrant liabilities		(4)
DOJ litigation settlement	0	0
Contingent consideration	0
Derivative financial instruments, liabilities	(6)	(37)
Estimated Fair Value | Level 2 | Demand deposits and savings accounts
Liabilities
Deposits	(4,998)	(4,956)
Estimated Fair Value | Level 2 | Certificates of deposit
Liabilities
Deposits	(1,159)	(1,062)
Estimated Fair Value | Level 2 | Government deposits
Liabilities
Deposits	(834)	(1,011)
Estimated Fair Value | Level 2 | Company controlled deposits
Liabilities
Deposits	(994)	(1,371)
Estimated Fair Value | Level 3
Assets
Cash and cash equivalents	0	0
Investment securities available-for-sale	0	0
Investment securities held-to-maturity	0	0
Loans held-for-sale	0	0
Loans held-for-investment	6,859	5,991
Loans with government guarantees	0	0
Mortgage servicing rights	184	335
Federal Home Loan Bank stock	0	0
Bank owned life insurance	0	0
Repossessed assets	9	14
Other assets, foreclosure claims	0	0
Derivative financial instruments, assets	27	24
Liabilities
Federal Home Loan Bank advances	0	0
Long-term debt	0	0
Warrant liabilities		0
DOJ litigation settlement	(60)	(60)
Contingent consideration	(23)
Derivative financial instruments, liabilities	(1)	(6)
Estimated Fair Value | Level 3 | Demand deposits and savings accounts
Liabilities
Deposits	0	0
Estimated Fair Value | Level 3 | Certificates of deposit
Liabilities
Deposits	0	0
Estimated Fair Value | Level 3 | Government deposits
Liabilities
Deposits	0	0
Estimated Fair Value | Level 3 | Company controlled deposits
Liabilities
Deposits	$ 0	$ 0