8.Notes Payable

Our senior unsecured notes and bonds consist of the following, sorted by maturity date (dollars in millions):

	March 31,			December 31,
	2016			2015
5.95% notes, issued in September 2006 and due in September 2016	$	275		$	275
5.375% notes, issued in September 2005 and due in September 2017	175			175
2.0% notes, issued in October 2012 and due in January 2018	350			350
6.75% notes, issued in September 2007 and due in August 2019	550			550
5.75% notes, issued in June 2010 and due in January 2021	250			250
3.25% notes, issued in October 2012 and due in October 2022	450			450
4.65% notes, issued in July 2013 and due in August 2023	750			750
3.875% notes, issued in June 2014 and due in July 2024	350			350
4.125% notes, issued in September 2014 and due in October 2026	250			250
5.875% bonds, $100 issued in March 2005 and $150 issued in
June 2011, both due in March 2035	250			250

Total principal amount	3,650			3,650
Unamortized original issuance discounts and deferred financing costs	(31		)	(32		)

	$	3,619		$	3,618

The following table summarizes the maturity of our notes and bonds payable as of March 31, 2016, excluding unamortized original issuance discounts and deferred financing costs (dollars in millions):

Year of Maturity	Principal
2016	$	275
2017	175
2018	350
2019	550
2020	-
Thereafter	2,300

Totals	$	3,650

As of March 31, 2016, the weighted average interest rate on our notes and bonds payable was 4.7% and the weighted average remaining years until maturity was 6.2 years.