9. Long-term Debt

A summary of Long-term Debt follows:

(Stated in millions)

	Mar. 31,		Dec. 31,
	2016		2015
4.00% Senior Notes due 2025	$	1,739	$	1,741
3.30% Senior Notes due 2021		1,593		1,597
3.00% Senior Notes due 2020		1,590		1,591
3.65% Senior Notes due 2023		1,490		1,496
2.35% Senior Notes due 2018		1,296		1,297
4.20% Senior Notes due 2021		1,099		1,100
1.25% Senior Notes due 2017		999		1,000
2.40% Senior Notes due 2022		995		999
3.63% Senior Notes due 2022		845		845
0.63% Guaranteed Notes due 2019		669		-
1.50% Guaranteed Notes due 2019		581		566
1.90% Senior Notes due 2017		498		499
Commercial paper borrowings		2,624		1,000
Other		1,215		711
	$	17,233	$	14,442

The estimated fair value of Schlumberger’s Long-term Debt at March 31, 2016 and December 31, 2015, based on quoted market prices, was $17.5 billion and $14.4 billion, respectively.

Borrowings under the commercial paper program at March 31, 2016 were $4.8 billion, of which $2.6 billion was classified within Long-term debt and $2.2 billion was classified within Long-term debt – current portion in the Consolidated Balance Sheet. At December 31, 2015, borrowings under the commercial paper program were $2.4 billion, of which $1.0 billion was classified within Long-term debt and $1.4 billion was classified within Long-term debt – current portion in the Consolidated Balance Sheet.