Following is the debt footnote from the Lowes 2017 form 10-K:

		12 Months Ended February 03, 2017
		Debt Category (In millions)	Weighted-Average Interest Rate at February 3, 201797				February 3, 2017							January 29, 2016
		Secured debt:
		Mortgage notes due through fiscal 2027 1	5.44%				$		7					$		7
		Unsecured debt:
		Notes due through fiscal 2021	2.87%				3,567							3,990
		Notes due fiscal 2022-2026	3.07%				3,783							2,443
		Notes due fiscal 2027-2031	6.76%				814							813
		Notes due fiscal 2032-2036	5.64%				941							941
		Notes due fiscal 2037-2041 2	5.94%				1,585							1,585
		Notes due fiscal 2042-2046	4.26%				3,631							2,301
		Capitalized lease obligations due through fiscal 2037				861							526
		Total long-term debt				15,189							12,606
		Less current maturities				(795)							(1,061)
		Long-term debt, excluding current maturities				$		14,394					$		11,545
	1 Real properties with an aggregate book value of $28 million were pledged as collateral at February 3, 2017, for secured debt.
	2 Amount includes $100 million of notes issued in 1997 that may be put at the option of the holder on the 20th anniversary of the issue at par value. None of these notes are currently puttable.

a. What is the amount of long-term debt on Lowes balance sheet as of February 3, 2017?

b. What proportion of Lowes long-term debt is due before February 2, 2018?

c. How much of Lowes assets were pledged as collateral as of February 3, 2017?