Other Fair Value Information (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term borrowings	$ 411,998		$ 12,000
Long-term debt	8,558,783		8,527,929
Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes and loans receivable	249,385	[1]	213,174	[1]
Short-term borrowings	411,998	[2]	12,000	[2]
Long-term debt	8,558,783	[2]	8,527,929	[2]
Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes and loans receivable	262,956	[1]	217,171	[1]
Short-term borrowings	411,998	[2]	12,000	[2]
Long-term debt	$ 8,662,603	[2]	$ 8,806,700	[2]

[1] Notes and loans receivable: The fair values are primarily measured using Level 2 and 3 inputs principally based on discounted future cash flows using market interest rates for similar instruments.

[2] Short-term borrowings and long-term debt: The fair values of short-term borrowings are estimated to be the carrying amount. The fair values of non-variable rate debt are estimated using quoted prices and estimated rates that would be available for debt with similar terms. The fair value of variable rate debt is estimated to be the carrying amount.