Investment Securities (Maturities of Available-for-Sale Debt Securities and Held-to-Maturity Debt Securities) (Details) (USD $) In Millions, unless otherwise specified
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Jun. 30, 2013
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Dec. 31, 2012
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Investment Holdings [Line Items] |
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Available-for-sale securities, debt maturities, one year or less, amortized cost |
$ 711 |
[1] |
|
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Available-for-sale securities, debt maturities, after one year through five years, amortized cost |
2,905 |
[1] |
|
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Available-for-sale securities, debt maturities, after five years through ten years, amortized cost |
347 |
[1] |
|
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Available-for-sale securities, debt maturities, after ten years, amortized cost |
862 |
[1] |
|
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Available-for-sale securities, debt maturities, amortized cost |
4,825 |
[1] |
|
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Held-to-maturity securities, debt maturities, one year or less, amortized cost |
2 |
[2] |
|
|
Held-to-maturity securities, debt maturities, after one year through five years, amortized cost |
1 |
[2] |
|
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Held-to-maturity securities, debt maturities, after five years through ten years, amortized cost |
0 |
[2] |
|
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Held-to-maturity securities, debt maturities, after ten years, amortized cost |
68 |
[2] |
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Held-to-maturity securities, debt maturities, amortized cost |
71 |
[2] |
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Available-for-sale securities, debt maturities, one year or less, fair value |
714 |
[1] |
|
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Available-for-sale debt maturities, after one year through five years, fair value |
2,964 |
[1] |
|
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Available-for-sale securities, debt maturities, after five years through ten years, fair value |
344 |
[1] |
|
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Available-for-sale securities, debt maturities, after ten years, fair value |
850 |
[1] |
|
|
Available-for-sale investment securities, fair value |
4,872 |
[1] |
6,145 |
[1] |
Held-to-maturity securities, debt maturities, one year or less, fair value |
2 |
[2] |
|
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Held-to-maturity securities, debt maturities, after one year through five years, fair value |
1 |
[2] |
|
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Held-to-maturity securities, debt maturities, after five years through ten years, fair value |
0 |
[2] |
|
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Held-to-maturity securities, debt maturities, after ten years, fair value |
67 |
[2] |
|
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Held-to-maturity securities, debt maturities, fair value |
70 |
[2] |
|
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US Treasury Securities [Member]
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Investment Holdings [Line Items] |
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Available-for-sale securities, debt maturities, one year or less, amortized cost |
540 |
[1] |
|
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Available-for-sale securities, debt maturities, after one year through five years, amortized cost |
1,496 |
[1] |
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Available-for-sale securities, debt maturities, after five years through ten years, amortized cost |
0 |
[1] |
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Available-for-sale securities, debt maturities, after ten years, amortized cost |
0 |
[1] |
|
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Available-for-sale securities, debt maturities, amortized cost |
2,036 |
[1] |
|
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Held-to-maturity securities, debt maturities, one year or less, amortized cost |
1 |
[2] |
|
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Held-to-maturity securities, debt maturities, after one year through five years, amortized cost |
0 |
[2] |
|
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Held-to-maturity securities, debt maturities, after five years through ten years, amortized cost |
0 |
[2] |
|
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Held-to-maturity securities, debt maturities, after ten years, amortized cost |
0 |
[2] |
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Held-to-maturity securities, debt maturities, amortized cost |
1 |
[2] |
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Available-for-sale securities, debt maturities, one year or less, fair value |
542 |
[1] |
|
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Available-for-sale debt maturities, after one year through five years, fair value |
1,525 |
[1] |
|
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Available-for-sale securities, debt maturities, after five years through ten years, fair value |
0 |
[1] |
|
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Available-for-sale securities, debt maturities, after ten years, fair value |
0 |
[1] |
|
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Available-for-sale investment securities, fair value |
2,067 |
[1] |
2,459 |
[1] |
Held-to-maturity securities, debt maturities, one year or less, fair value |
1 |
[2] |
|
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Held-to-maturity securities, debt maturities, after one year through five years, fair value |
0 |
[2] |
|
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Held-to-maturity securities, debt maturities, after five years through ten years, fair value |
0 |
[2] |
|
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Held-to-maturity securities, debt maturities, after ten years, fair value |
0 |
[2] |
|
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Held-to-maturity securities, debt maturities, fair value |
1 |
[2] |
|
|
US Government Corporations and Agencies Securities [Member]
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|
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Investment Holdings [Line Items] |
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|
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Available-for-sale securities, debt maturities, one year or less, amortized cost |
131 |
[1] |
|
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Available-for-sale securities, debt maturities, after one year through five years, amortized cost |
1,409 |
[1] |
|
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Available-for-sale securities, debt maturities, after five years through ten years, amortized cost |
0 |
[1] |
|
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Available-for-sale securities, debt maturities, after ten years, amortized cost |
0 |
[1] |
|
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Available-for-sale securities, debt maturities, amortized cost |
1,540 |
[1] |
|
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Available-for-sale securities, debt maturities, one year or less, fair value |
131 |
[1] |
|
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Available-for-sale debt maturities, after one year through five years, fair value |
1,439 |
[1] |
|
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Available-for-sale securities, debt maturities, after five years through ten years, fair value |
0 |
[1] |
|
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Available-for-sale securities, debt maturities, after ten years, fair value |
0 |
[1] |
|
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Available-for-sale investment securities, fair value |
1,570 |
[1] |
2,233 |
[1] |
Asset-backed Securities, Securitized Loans and Receivables [Member]
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Investment Holdings [Line Items] |
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Available-for-sale securities, debt maturities, one year or less, amortized cost |
40 |
[1] |
|
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Available-for-sale securities, debt maturities, after one year through five years, amortized cost |
0 |
[1] |
|
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Available-for-sale securities, debt maturities, after five years through ten years, amortized cost |
0 |
[1] |
|
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Available-for-sale securities, debt maturities, after ten years, amortized cost |
0 |
[1] |
|
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Available-for-sale securities, debt maturities, amortized cost |
40 |
[1] |
|
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Available-for-sale securities, debt maturities, one year or less, fair value |
41 |
[1] |
|
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Available-for-sale debt maturities, after one year through five years, fair value |
0 |
[1] |
|
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Available-for-sale securities, debt maturities, after five years through ten years, fair value |
0 |
[1] |
|
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Available-for-sale securities, debt maturities, after ten years, fair value |
0 |
[1] |
|
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Available-for-sale investment securities, fair value |
41 |
[1] |
151 |
[1] |
US States and Political Subdivisions Debt Securities [Member]
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Investment Holdings [Line Items] |
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Held-to-maturity securities, debt maturities, one year or less, amortized cost |
1 |
[2] |
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Held-to-maturity securities, debt maturities, after one year through five years, amortized cost |
1 |
[2] |
|
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Held-to-maturity securities, debt maturities, after five years through ten years, amortized cost |
0 |
[2] |
|
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Held-to-maturity securities, debt maturities, after ten years, amortized cost |
22 |
[2] |
|
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Held-to-maturity securities, debt maturities, amortized cost |
24 |
[2] |
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Held-to-maturity securities, debt maturities, one year or less, fair value |
1 |
[2] |
|
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Held-to-maturity securities, debt maturities, after one year through five years, fair value |
1 |
[2] |
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Held-to-maturity securities, debt maturities, after five years through ten years, fair value |
0 |
[2] |
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Held-to-maturity securities, debt maturities, after ten years, fair value |
21 |
[2] |
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Held-to-maturity securities, debt maturities, fair value |
23 |
[2] |
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Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
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Investment Holdings [Line Items] |
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Available-for-sale securities, debt maturities, one year or less, amortized cost |
0 |
[1] |
|
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Available-for-sale securities, debt maturities, after one year through five years, amortized cost |
0 |
[1] |
|
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Available-for-sale securities, debt maturities, after five years through ten years, amortized cost |
347 |
[1] |
|
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Available-for-sale securities, debt maturities, after ten years, amortized cost |
862 |
[1] |
|
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Available-for-sale securities, debt maturities, amortized cost |
1,209 |
[1] |
|
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Held-to-maturity securities, debt maturities, one year or less, amortized cost |
0 |
[2],[3] |
|
|
Held-to-maturity securities, debt maturities, after one year through five years, amortized cost |
0 |
[2],[3] |
|
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Held-to-maturity securities, debt maturities, after five years through ten years, amortized cost |
0 |
[2],[3] |
|
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Held-to-maturity securities, debt maturities, after ten years, amortized cost |
46 |
[2],[3] |
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Held-to-maturity securities, debt maturities, amortized cost |
46 |
[2],[3] |
|
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Available-for-sale securities, debt maturities, one year or less, fair value |
0 |
[1] |
|
|
Available-for-sale debt maturities, after one year through five years, fair value |
0 |
[1] |
|
|
Available-for-sale securities, debt maturities, after five years through ten years, fair value |
344 |
[1] |
|
|
Available-for-sale securities, debt maturities, after ten years, fair value |
850 |
[1] |
|
|
Available-for-sale investment securities, fair value |
1,194 |
[1] |
1,302 |
[1] |
Held-to-maturity securities, debt maturities, one year or less, fair value |
0 |
[2],[3] |
|
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Held-to-maturity securities, debt maturities, after one year through five years, fair value |
0 |
[2],[3] |
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Held-to-maturity securities, debt maturities, after five years through ten years, fair value |
0 |
[2],[3] |
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Held-to-maturity securities, debt maturities, after ten years, fair value |
46 |
[2],[3] |
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Held-to-maturity securities, debt maturities, fair value |
$ 46 |
[2],[3] |
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