Retirement Plans (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Components of net periodic pension cost
Service cost	$ 15	$ 12	$ 43	$ 36
Interest cost	23	22	67	66
Expected return on plan assets	(28)	(21)	(82)	(63)
Amortization of net loss	13	12	35	36
Pension expense	23	25	63	75
Retirement Plans (Textual) [Abstract]
Corporation expects to contribute to its pension plan in 2011	190		190
Corporation contributed to its pension plan			$ 148