Loans and Allowance for Loan Losses (Details 2) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Comparison of delinquent loans by class
Total Past Due	$ 1,556,338	$ 1,483,410
Current Loans	28,491,084	29,440,487
Total Loans	30,047,422	30,923,897
90 Days or more accruing	84,670	64,156
30-59 Days [Member]
Comparison of delinquent loans by class
Total Past Due	405,913	418,906
30-59 Days [Member] | One- to four-family, Amortizing [Member]
Comparison of delinquent loans by class
Total Past Due	327,983	363,583
30-59 Days [Member] | One- to four-family, Interest-only [Member]
Comparison of delinquent loans by class
Total Past Due	74,941	47,479
30-59 Days [Member] | Multi-family and commercial mortgages [Member]
Comparison of delinquent loans by class
Total Past Due	240	3,199
30-59 Days [Member] | Construction loans [Member]
Comparison of delinquent loans by class
Total Past Due	0	0
30-59 Days [Member] | Fixed-rate second mortgages [Member]
Comparison of delinquent loans by class
Total Past Due	619	896
30-59 Days [Member] | Home equity credit lines [Member]
Comparison of delinquent loans by class
Total Past Due	2,078	2,419
30-59 Days [Member] | Other [Member]
Comparison of delinquent loans by class
Total Past Due	52	1,330
60-89 Days [Member]
Comparison of delinquent loans by class
Total Past Due	201,719	193,245
60-89 Days [Member] | One- to four-family, Amortizing [Member]
Comparison of delinquent loans by class
Total Past Due	167,469	161,530
60-89 Days [Member] | One- to four-family, Interest-only [Member]
Comparison of delinquent loans by class
Total Past Due	30,576	29,570
60-89 Days [Member] | Multi-family and commercial mortgages [Member]
Comparison of delinquent loans by class
Total Past Due	2,474	1,199
60-89 Days [Member] | Construction loans [Member]
Comparison of delinquent loans by class
Total Past Due	0	0
60-89 Days [Member] | Fixed-rate second mortgages [Member]
Comparison of delinquent loans by class
Total Past Due	624	240
60-89 Days [Member] | Home equity credit lines [Member]
Comparison of delinquent loans by class
Total Past Due	575	703
60-89 Days [Member] | Other [Member]
Comparison of delinquent loans by class
Total Past Due	1	3
90 Days or more [Member]
Comparison of delinquent loans by class
Total Past Due	948,706	871,259
90 Days or more [Member] | One- to four-family, Amortizing [Member]
Comparison of delinquent loans by class
Total Past Due	736,751	678,914
90 Days or more [Member] | One- to four-family, Interest-only [Member]
Comparison of delinquent loans by class
Total Past Due	199,696	179,348
90 Days or more [Member] | Multi-family and commercial mortgages [Member]
Comparison of delinquent loans by class
Total Past Due	525	1,117
90 Days or more [Member] | Construction loans [Member]
Comparison of delinquent loans by class
Total Past Due	6,902	7,560
90 Days or more [Member] | Fixed-rate second mortgages [Member]
Comparison of delinquent loans by class
Total Past Due	567	440
90 Days or more [Member] | Home equity credit lines [Member]
Comparison of delinquent loans by class
Total Past Due	3,644	2,356
90 Days or more [Member] | Other [Member]
Comparison of delinquent loans by class
Total Past Due	621	1,524
One- to four-family, Amortizing [Member]
Comparison of delinquent loans by class
Total Past Due	1,232,203	1,204,027
Current Loans	23,574,558	24,208,632
Total Loans	24,806,761	25,412,659
90 Days or more accruing	84,670	64,156
One- to four-family, Interest-only [Member]
Comparison of delinquent loans by class
Total Past Due	305,213	256,397
Current Loans	4,592,377	4,880,066
Total Loans	4,897,590	5,136,463
90 Days or more accruing	0	0
Multi-family and commercial mortgages [Member]
Comparison of delinquent loans by class
Total Past Due	3,239	5,515
Current Loans	36,719	42,552
Total Loans	39,958	48,067
90 Days or more accruing	0	0
Construction loans [Member]
Comparison of delinquent loans by class
Total Past Due	6,902	7,560
Current Loans	1,097	1,521
Total Loans	7,999	9,081
90 Days or more accruing	0	0
Fixed-rate second mortgages [Member]
Comparison of delinquent loans by class
Total Past Due	1,810	1,576
Current Loans	136,957	159,320
Total Loans	138,767	160,896
90 Days or more accruing	0	0
Home equity credit lines [Member]
Comparison of delinquent loans by class
Total Past Due	6,297	5,478
Current Loans	129,575	131,989
Total Loans	135,872	137,467
90 Days or more accruing	0	0
Other [Member]
Comparison of delinquent loans by class
Total Past Due	674	2,857
Current Loans	19,801	16,407
Total Loans	20,475	19,264
90 Days or more accruing	$ 0	$ 0