Contractual maturities of investment securities, excluding equity securities and other securities, as of December 31, 2013 were as follows:
| Estimated | |||||||
| (Millions) | Cost | Fair Value | |||||
| Due within 1 year | $ | 505 | $ | 505 | |||
| Due after 1 year but within 5 years | 489 | 496 | |||||
| Due after 5 years but within 10 years | 215 | 224 | |||||
| Due after 10 years | 3,647 | 3,619 | |||||
| Total | $ | 4,856 | $ | 4,844 | |||