Loans and Allowance for Loan Losses (Details 2) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Comparison of delinquent loans by class
Total Past Due	$ 1,493,215	$ 1,483,410
Current Loans	28,880,260	29,440,487
Total Loans	30,373,476	30,923,897
90 Days or more accruing	75,345	64,156
30-59 Days [Member]
Comparison of delinquent loans by class
Total Past Due	408,536	418,906
30-59 Days [Member] | One- to four-family, Amortizing [Member]
Comparison of delinquent loans by class
Total Past Due	338,590	363,583
30-59 Days [Member] | One- to four-family, Interest-only [Member]
Comparison of delinquent loans by class
Total Past Due	65,416	47,479
30-59 Days [Member] | Multi-family and commercial mortgages [Member]
Comparison of delinquent loans by class
Total Past Due	1,334	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	832	896
30-59 Days [Member] | Home equity credit lines [Member]
Comparison of delinquent loans by class
Total Past Due	1,739	2,419
30-59 Days [Member] | Other [Member]
Comparison of delinquent loans by class
Total Past Due	625	1,330
60-89 Days [Member]
Comparison of delinquent loans by class
Total Past Due	170,441	193,245
60-89 Days [Member] | One- to four-family, Amortizing [Member]
Comparison of delinquent loans by class
Total Past Due	141,260	161,530
60-89 Days [Member] | One- to four-family, Interest-only [Member]
Comparison of delinquent loans by class
Total Past Due	26,618	29,570
60-89 Days [Member] | Multi-family and commercial mortgages [Member]
Comparison of delinquent loans by class
Total Past Due	1,717	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	217	240
60-89 Days [Member] | Home equity credit lines [Member]
Comparison of delinquent loans by class
Total Past Due	589	703
60-89 Days [Member] | Other [Member]
Comparison of delinquent loans by class
Total Past Due	40	3
Ninety Days Or More Past Due [Member]
Comparison of delinquent loans by class
Total Past Due	914,239	871,259
Ninety Days Or More Past Due [Member] | One- to four-family, Amortizing [Member]
Comparison of delinquent loans by class
Total Past Due	710,635	678,914
Ninety Days Or More Past Due [Member] | One- to four-family, Interest-only [Member]
Comparison of delinquent loans by class
Total Past Due	192,283	179,348
Ninety Days Or More Past Due [Member] | Multi-family and commercial mortgages [Member]
Comparison of delinquent loans by class
Total Past Due	531	1,117
Ninety Days Or More Past Due [Member] | Construction loans [Member]
Comparison of delinquent loans by class
Total Past Due	7,002	7,560
Ninety Days Or More Past Due [Member] | Fixed-rate second mortgages [Member]
Comparison of delinquent loans by class
Total Past Due	462	440
Ninety Days Or More Past Due [Member] | Home equity credit lines [Member]
Comparison of delinquent loans by class
Total Past Due	3,266	2,356
Ninety Days Or More Past Due [Member] | Other [Member]
Comparison of delinquent loans by class
Total Past Due	60	1,524
One- to four-family, Amortizing [Member]
Comparison of delinquent loans by class
Total Past Due	1,190,485	1,204,027
Current Loans	23,766,467	24,208,632
Total Loans	24,956,952	25,412,659
90 Days or more accruing	75,345	64,156
One- to four-family, Interest-only [Member]
Comparison of delinquent loans by class
Total Past Due	284,317	256,397
Current Loans	4,781,223	4,880,066
Total Loans	5,065,540	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	3,582	5,515
Current Loans	38,878	42,552
Total Loans	42,460	48,067
90 Days or more accruing	0	0
Construction loans [Member]
Comparison of delinquent loans by class
Total Past Due	7,002	7,560
Current Loans	1,366	1,521
Total Loans	8,368	9,081
90 Days or more accruing	0	0
Fixed-rate second mortgages [Member]
Comparison of delinquent loans by class
Total Past Due	1,511	1,576
Current Loans	143,235	159,320
Total Loans	144,746	160,896
90 Days or more accruing	0	0
Home equity credit lines [Member]
Comparison of delinquent loans by class
Total Past Due	5,594	5,478
Current Loans	129,094	131,989
Total Loans	134,688	137,467
90 Days or more accruing	0	0
Other [Member]
Comparison of delinquent loans by class
Total Past Due	725	2,857
Current Loans	19,997	16,407
Total Loans	20,722	19,264
90 Days or more accruing	$ 0	$ 0