Debt	3 Months Ended
Mar. 31, 2014
Debt
Debt	Note 12—Debt *Revolving Credit Facility* The Company has a $1,500,000 unsecured credit facility (the “Revolving Credit Facility”) with a maturity date of July 2018. At March 31, 2014, borrowings and availability under the Revolving Credit Facility were $270,000 and $1,230,000, respectively. As of March 31, 2014, the interest rate on borrowings under the Revolving Credit Facility was at a spread over LIBOR. The Revolving Credit Facility requires payment of certain annual agency and commitment fees and requires that the Company satisfy certain financial covenants. *Senior Notes* In November 2009, the Company issued $600,000 principal amount of unsecured 4.75% Senior Notes due November 2014 (the “4.75% Senior Notes”) at 99.813% of their face value. Interest on the 4.75% Senior Notes is payable semi-annually on May 15 and November 15 of each year to the holders of record as of the immediately preceding May 1 and November 1. The Company may, at its option, redeem some or all of the 4.75% Senior Notes at any time by paying a make-whole premium, plus accrued and unpaid interest, if any, to the date of repurchase. The 4.75% Senior Notes are unsecured and rank equally in right of payment with the Company’s other unsecured senior indebtedness. The fair value of the 4.75% Senior Notes at March 31, 2014 was approximately $615,900 based on recent bid prices in an active market and are therefore classified as Level 1 in the fair value hierarchy. In January 2012, the Company issued $500,000 principal amount of unsecured 4.00% Senior Notes due February 2022 (the “4.00% Senior Notes”) at 99.746% of their face value. Interest on the 4.00% Senior Notes is payable semi-annually on February 1 and August 1 of each year, to the holders of record as of the immediately preceding January 15 and July 15. The Company may, at its option, redeem some or all of the 4.00% Senior Notes at any time by paying 100% of the principal amount, plus accrued and unpaid interest, if any, to the date of repurchase, and if redeemed prior to November 1, 2021, a make-whole premium. The 4.00% Senior Notes are unsecured and rank equally in right of payment with the Company’s other unsecured senior indebtedness. The fair value of the 4.00% Senior Notes at March 31, 2014 was approximately $503,200 based on recent bid prices in an active market and are therefore classified as Level 1 in the fair value hierarchy. In January 2014, the Company issued $750,000 principal amount of unsecured 2.55% Senior Notes due January 2019 (the “2.55% Senior Notes”) at 99.846% of their face value. Interest on the 2.55% Senior Notes is payable semi-annually on January 30 and July 30 of each year, commencing July 30, 2014, to the holders of record as of the immediately preceding January 15 and July 15. The Company may, at its option, redeem some or all of the 2.55% Senior Notes at any time by paying 100% of the principal amount, plus accrued and unpaid interest, if any, to the date of redemption, and if redeemed prior to December 30, 2018, a make-whole premium. The 2.55% Senior Notes are unsecured and rank equally in right of payment with the Company’s other unsecured senior indebtedness. The fair value of the 2.55% Senior Notes at March 31, 2014 was approximately $750,375 based on recent bid prices in an active market and are therefore classified as Level 1 in the fair value hierarchy. *Credit Agreement* The Company has a $100,000 uncommitted and unsecured credit facility with the ability to borrow at a spread over LIBOR, which is renewable annually (the “Credit Agreement”). At March 31, 2014, borrowings and availability under the Credit Agreement were $100,000 and nil, respectively. The carrying value of borrowings under the Company’s Revolving Credit Facility and Credit Agreement approximated their fair value at March 31, 2014 due to their relative short-term maturities and market interest rates and are therefore classified as Level 2 in the fair value hierarchy.

Note 12—Debt

Revolving Credit Facility

The Company has a $1,500,000 unsecured credit facility (the “Revolving Credit Facility”) with a maturity date of July 2018. At March 31, 2014, borrowings and availability under the Revolving Credit Facility were $270,000 and $1,230,000, respectively. As of March 31, 2014, the interest rate on borrowings under the Revolving Credit Facility was at a spread over LIBOR. The Revolving Credit Facility requires payment of certain annual agency and commitment fees and requires that the Company satisfy certain financial covenants.

Senior Notes

In November 2009, the Company issued $600,000 principal amount of unsecured 4.75% Senior Notes due November 2014 (the “4.75% Senior Notes”) at 99.813% of their face value. Interest on the 4.75% Senior Notes is payable semi-annually on May 15 and November 15 of each year to the holders of record as of the immediately preceding May 1 and November 1. The Company may, at its option, redeem some or all of the 4.75% Senior Notes at any time by paying a make-whole premium, plus accrued and unpaid interest, if any, to the date of repurchase. The 4.75% Senior Notes are unsecured and rank equally in right of payment with the Company’s other unsecured senior indebtedness. The fair value of the 4.75% Senior Notes at March 31, 2014 was approximately $615,900 based on recent bid prices in an active market and are therefore classified as Level 1 in the fair value hierarchy.

In January 2012, the Company issued $500,000 principal amount of unsecured 4.00% Senior Notes due February 2022 (the “4.00% Senior Notes”) at 99.746% of their face value. Interest on the 4.00% Senior Notes is payable semi-annually on February 1 and August 1 of each year, to the holders of record as of the immediately preceding January 15 and July 15. The Company may, at its option, redeem some or all of the 4.00% Senior Notes at any time by paying 100% of the principal amount, plus accrued and unpaid interest, if any, to the date of repurchase, and if redeemed prior to November 1, 2021, a make-whole premium. The 4.00% Senior Notes are unsecured and rank equally in right of payment with the Company’s other unsecured senior indebtedness. The fair value of the 4.00% Senior Notes at March 31, 2014 was approximately $503,200 based on recent bid prices in an active market and are therefore classified as Level 1 in the fair value hierarchy.

In January 2014, the Company issued $750,000 principal amount of unsecured 2.55% Senior Notes due January 2019 (the “2.55% Senior Notes”) at 99.846% of their face value. Interest on the 2.55% Senior Notes is payable semi-annually on January 30 and July 30 of each year, commencing July 30, 2014, to the holders of record as of the immediately preceding January 15 and July 15. The Company may, at its option, redeem some or all of the 2.55% Senior Notes at any time by paying 100% of the principal amount, plus accrued and unpaid interest, if any, to the date of redemption, and if redeemed prior to December 30, 2018, a make-whole premium. The 2.55% Senior Notes are unsecured and rank equally in right of payment with the Company’s other unsecured senior indebtedness. The fair value of the 2.55% Senior Notes at March 31, 2014 was approximately $750,375 based on recent bid prices in an active market and are therefore classified as Level 1 in the fair value hierarchy.

Credit Agreement

The Company has a $100,000 uncommitted and unsecured credit facility with the ability to borrow at a spread over LIBOR, which is renewable annually (the “Credit Agreement”). At March 31, 2014, borrowings and availability under the Credit Agreement were $100,000 and nil, respectively.

The carrying value of borrowings under the Company’s Revolving Credit Facility and Credit Agreement approximated their fair value at March 31, 2014 due to their relative short-term maturities and market interest rates and are therefore classified as Level 2 in the fair value hierarchy.