Debt (Parenthetical) (Details)	Jun. 30, 2014	Apr. 25, 2014
7% Notes due 2013
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.00%
3.75% Senior Notes due 2021
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.75%
6 5/8% Senior Notes due 2029
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.625%
6.25% Senior Notes due 2032
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.25%
4.35% Senior Notes due 2044
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.35%	4.35%
6.70% Fixed-to-Floating Rate Junior Subordinated Debentures due 2067
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.70%