Allowance for Loan Losses (Details 3) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2011	Dec. 31, 2010
School Type/FICO [Member] | Private Education Loans [Member]
Key credit quality indicators of the Company's loan portfolio
School type FICO scores traditional recorded investment	$ 33,790	$ 33,619
School type FICO scores traditional recorded investment, in percent	90.00%	90.00%
School type FICO scores non traditional recorded investment	3,727	3,913
School type FICO scores non traditional recorded investment, in percent	10.00%	10.00%
Total	37,517	37,532
Total, in percent	100.00%	100.00%
Seasoning [Member] | Private Education Loans [Member]
Key credit quality indicators of the Company's loan portfolio
Seasoning - based on monthly scheduled payments due from 1-12 payments	10,793	10,932
Seasoning based on monthly scheduled payments due from 1-12 payments, in percent	29.00%	29.00%
Seasoning - based on monthly scheduled payments due from 13-24 payments	6,625	6,659
Seasoning based on monthly scheduled payments due from 13 - 24 payments, in percent	18.00%	18.00%
Seasoning - based on monthly scheduled payments due from 25-36 payments	4,592	4,457
Seasoning based on monthly scheduled payments due from 25 - 36 payments, in percent	12.00%	12.00%
Seasoning - based on monthly scheduled payments due from 37-48 payments	3,267	2,891
Seasoning based on monthly scheduled payments due from 37 - 48 payments, in percent	9.00%	8.00%
Seasoning - based on monthly scheduled payments due from more than 48 payments	5,024	4,253
Seasoning based on monthly scheduled payments due from more than 48 payments, in percent	13.00%	11.00%
Seasoning - based on monthly scheduled payments due from not yet in repayment	7,216	8,340
Seasoning - based on monthly scheduled payments due from not yet in repayment, in percent	19.00%	22.00%
Total seasoning - based on monthly scheduled payments due	37,517	37,532
Total seasoning - based on monthly scheduled payments due, in percent	100.00%	100.00%
Cosigner [Member]
Key credit quality indicators of the Company's loan portfolio
Cosigners recorded investment with cosigner	22,650	22,259
Cosigners recorded investment without cosigner	14,867	15,273
Total cosigners recorded investment	$ 37,517	$ 37,532
Cosigner [Member] | Private Education Loans [Member]
Key credit quality indicators of the Company's loan portfolio
Cosigners recorded investment with cosigner, in percent	60.00%	59.00%
Cosigners recorded investment without cosigner, in percent	40.00%	41.00%
Total cosigners recorded investment, in percent	100.00%	100.00%