Allowance for Loan Losses (Details 1) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2011	Dec. 31, 2010
FFELP Loans [Member]
Age analysis of past due loans delinquencies
Loans in-school/grace/deferment	$ 25,718	$ 28,214
Loans in forbearance	21,048	22,028
Loans in repayment and percentage of each status:
Loans current	78,201	80,026
Loans current, in percentage	82.90%	82.80%
Loans delinquent 31-60 days	5,149	5,500
Loans delinquent 31-60 days, in percentage	5.50%	5.70%
Loans delinquent 61-90 days	2,909	3,178
Loans delinquent 61-90 days, in percentage	3.10%	3.30%
Loans delinquent greater than 90 days	8,023	7,992
Loans delinquent greater than 90 days, in percentage	8.50%	8.20%
Total loans in repayment	94,282	96,696
Total loans in repayment, in percentage	100.00%	100.00%
Total loans, gross	141,048	146,938
Loans unamortized premium (discount)	1,776	1,900
Total loans	142,824	148,838
Loans allowance for losses	(189)	(189)
Loans, net	142,635	148,649
Percentage of loans in repayment	66.80%	65.80%
Delinquencies as a percentage of loans in repayment	17.10%	17.20%
Loans in forbearance as a percentage of loans in repayment and forbearance	18.20%	18.60%
Private Education Loans - Traditional [Member]
Age analysis of past due loans delinquencies
Loans in-school/grace/deferment	6,431	7,419
Loans in forbearance	1,225	1,156
Loans in repayment and percentage of each status:
Loans current	23,964	22,850
Loans current, in percentage	91.70%	91.20%
Loans delinquent 31-60 days	759	794
Loans delinquent 31-60 days, in percentage	2.90%	3.20%
Loans delinquent 61-90 days	433	340
Loans delinquent 61-90 days, in percentage	1.70%	1.40%
Loans delinquent greater than 90 days	978	1,060
Loans delinquent greater than 90 days, in percentage	3.70%	4.20%
Total loans in repayment	26,134	25,044
Total loans in repayment, in percentage	100.00%	100.00%
Total loans, gross	33,790	33,619
Loans unamortized premium (discount)	(775)	(801)
Total loans	33,015	32,818
Loans receivable for partially charged-off loans	629	558
Loans allowance for losses	(1,363)	(1,231)
Loans, net	32,281	32,145
Percentage of loans in repayment	77.30%	74.50%
Delinquencies as a percentage of loans in repayment	8.30%	8.80%
Loans in forbearance as a percentage of loans in repayment and forbearance	4.50%	4.40%
Loans in repayment greater than 12 months as a percentage of loans in repayment	66.70%	65.20%
Private Education Loans - Non-Traditional [Member]
Age analysis of past due loans delinquencies
Loans in-school/grace/deferment	785	921
Loans in forbearance	205	184
Loans in repayment and percentage of each status:
Loans current	2,030	2,038
Loans current, in percentage	74.10%	72.60%
Loans delinquent 31-60 days	204	217
Loans delinquent 31-60 days, in percentage	7.50%	7.70%
Loans delinquent 61-90 days	142	131
Loans delinquent 61-90 days, in percentage	5.20%	4.70%
Loans delinquent greater than 90 days	361	422
Loans delinquent greater than 90 days, in percentage	13.20%	15.00%
Total loans in repayment	2,737	2,808
Total loans in repayment, in percentage	100.00%	100.00%
Total loans, gross	3,727	3,913
Loans unamortized premium (discount)	(86)	(93)
Total loans	3,641	3,820
Loans receivable for partially charged-off loans	511	482
Loans allowance for losses	(680)	(791)
Loans, net	$ 3,472	$ 3,511
Percentage of loans in repayment	73.50%	71.80%
Delinquencies as a percentage of loans in repayment	25.90%	27.40%
Loans in forbearance as a percentage of loans in repayment and forbearance	7.00%	6.10%
Loans in repayment greater than 12 months as a percentage of loans in repayment	60.00%	55.90%