Loans (Schedule Of Consumer Loan LTV Distributions) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 29,113.9	$ 29,535.9	$ 30,518.7
Reverse Mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans transferred to AHFS	861.0
Consumer Portfolio
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,536.0	6,565.2
Consumer Portfolio | Greater than 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	170.4	319.1
Consumer Portfolio | 101% — 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	302.3	483.8
Consumer Portfolio | 80% — 100%
Financing Receivable, Recorded Investment [Line Items]
Total loans	780.9	929.0
Consumer Portfolio | Less than 80%
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,281.6	4,830.4
Consumer Portfolio | Not Applicable
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.8	2.9
Consumer Portfolio | Single Family Residential
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,536.0	5,706.3
Consumer Portfolio | Single Family Residential | Greater than 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	170.4	275.9
Consumer Portfolio | Single Family Residential | 101% — 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	302.3	462.0
Consumer Portfolio | Single Family Residential | 80% — 100%
Financing Receivable, Recorded Investment [Line Items]
Total loans	780.9	855.2
Consumer Portfolio | Single Family Residential | Less than 80%
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,281.6	4,110.3
Consumer Portfolio | Single Family Residential | Not Applicable
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.8	2.9
Consumer Portfolio | Reverse Mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	858.9
Consumer Portfolio | Reverse Mortgage | Greater than 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	43.2
Consumer Portfolio | Reverse Mortgage | 101% — 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	21.8
Consumer Portfolio | Reverse Mortgage | 80% — 100%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	73.8
Consumer Portfolio | Reverse Mortgage | Less than 80%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	720.1
Consumer Portfolio | Reverse Mortgage | Not Applicable
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	0.0
Covered Loans | Reverse Mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans transferred to AHFS	411.0
Covered Loans | Consumer Portfolio | Single Family Residential
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,392.6	1,749.1
Covered Loans | Consumer Portfolio | Single Family Residential | Greater than 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	2.7	2.2
Covered Loans | Consumer Portfolio | Single Family Residential | 101% — 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	6.4	4.7
Covered Loans | Consumer Portfolio | Single Family Residential | 80% — 100%
Financing Receivable, Recorded Investment [Line Items]
Total loans	77.4	226.6
Covered Loans | Consumer Portfolio | Single Family Residential | Less than 80%
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,306.1	1,515.6
Covered Loans | Consumer Portfolio | Single Family Residential | Not Applicable
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	0.0
Covered Loans | Consumer Portfolio | Reverse Mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	431.2
Covered Loans | Consumer Portfolio | Reverse Mortgage | Greater than 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	0.6
Covered Loans | Consumer Portfolio | Reverse Mortgage | 101% — 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	1.2
Covered Loans | Consumer Portfolio | Reverse Mortgage | 80% — 100%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	24.0
Covered Loans | Consumer Portfolio | Reverse Mortgage | Less than 80%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	405.4
Covered Loans | Consumer Portfolio | Reverse Mortgage | Not Applicable
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	0.0
Covered Loans | Consumer Portfolio | PCI Loans | Single Family Residential
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,895.8	2,165.6
Covered Loans | Consumer Portfolio | PCI Loans | Single Family Residential | Greater than 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	160.0	261.4
Covered Loans | Consumer Portfolio | PCI Loans | Single Family Residential | 101% — 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	291.5	443.7
Covered Loans | Consumer Portfolio | PCI Loans | Single Family Residential | 80% — 100%
Financing Receivable, Recorded Investment [Line Items]
Total loans	566.2	588.1
Covered Loans | Consumer Portfolio | PCI Loans | Single Family Residential | Less than 80%
Financing Receivable, Recorded Investment [Line Items]
Total loans	878.1	872.4
Covered Loans | Consumer Portfolio | PCI Loans | Single Family Residential | Not Applicable
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	0.0
Non-covered Loans | Consumer Portfolio | Single Family Residential
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,239.9	1,782.4
Non-covered Loans | Consumer Portfolio | Single Family Residential | Greater than 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	7.7	12.3
Non-covered Loans | Consumer Portfolio | Single Family Residential | 101% — 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	4.4	13.6
Non-covered Loans | Consumer Portfolio | Single Family Residential | 80% — 100%
Financing Receivable, Recorded Investment [Line Items]
Total loans	137.3	40.5
Non-covered Loans | Consumer Portfolio | Single Family Residential | Less than 80%
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,089.7	1,713.1
Non-covered Loans | Consumer Portfolio | Single Family Residential | Not Applicable
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.8	2.9
Non-covered Loans | Consumer Portfolio | Reverse Mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	368.7
Non-covered Loans | Consumer Portfolio | Reverse Mortgage | Greater than 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	8.8
Non-covered Loans | Consumer Portfolio | Reverse Mortgage | 101% — 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	12.7
Non-covered Loans | Consumer Portfolio | Reverse Mortgage | 80% — 100%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	42.3
Non-covered Loans | Consumer Portfolio | Reverse Mortgage | Less than 80%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	304.9
Non-covered Loans | Consumer Portfolio | Reverse Mortgage | Not Applicable
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	0.0
Non-covered Loans | Consumer Portfolio | PCI Loans | Single Family Residential
Financing Receivable, Recorded Investment [Line Items]
Total loans	7.7	9.2
Non-covered Loans | Consumer Portfolio | PCI Loans | Single Family Residential | Greater than 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	0.0
Non-covered Loans | Consumer Portfolio | PCI Loans | Single Family Residential | 101% — 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	0.0
Non-covered Loans | Consumer Portfolio | PCI Loans | Single Family Residential | 80% — 100%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	0.0
Non-covered Loans | Consumer Portfolio | PCI Loans | Single Family Residential | Less than 80%
Financing Receivable, Recorded Investment [Line Items]
Total loans	7.7	9.2
Non-covered Loans | Consumer Portfolio | PCI Loans | Single Family Residential | Not Applicable
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	0.0
Non-covered Loans | Consumer Portfolio | PCI Loans | Reverse Mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	59.0
Non-covered Loans | Consumer Portfolio | PCI Loans | Reverse Mortgage | Greater than 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	33.8
Non-covered Loans | Consumer Portfolio | PCI Loans | Reverse Mortgage | 101% — 125%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	7.9
Non-covered Loans | Consumer Portfolio | PCI Loans | Reverse Mortgage | 80% — 100%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	7.5
Non-covered Loans | Consumer Portfolio | PCI Loans | Reverse Mortgage | Less than 80%
Financing Receivable, Recorded Investment [Line Items]
Total loans	0.0	9.8
Non-covered Loans | Consumer Portfolio | PCI Loans | Reverse Mortgage | Not Applicable
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 0.0	$ 0.0