Common Stock (Details) (Pension Plan, Defined Benefit [Member], Common Stock [Member], USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended				12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2012	Dec. 31, 2013
Pension Plan, Defined Benefit [Member] | Common Stock [Member]
Class of Stock [Line Items]
Stock Issued During Period, Shares, Employee Benefit Plan	1,522,301	753,579	750,075	1,334,668
Contribution of Common Stock to Pension Plans Amount Per Share	$ 65.69	$ 66.35	$ 66.66	$ 59.94
Pension Contributions	$ 100	$ 50	$ 50	$ 80	$ 200