2019

2018

Revolving credit facility (weighted average interest rate of 3.1% as of December 31, 2018)

$

—

$

11

Commercial paper program (weighted average interest rate of 2.9% as of December 31, 2018)

—

990

Senior notes, maturing through 2049, interest rates ranging from 2.4% to 7.75% (weighted average interest rate of 3.9% as of December 31, 2019 and 4.3% as of December 31, 2018)

9,965

6,222

Canadian senior notes, maturing September 2026, interest rate of 2.6%

385

—

Tax-exempt bonds, maturing through 2048, fixed and variable interest rates ranging from 1.35% to 4.3% (weighted average interest rate of 2.3% as of December 31, 2019 and 2.35% as of December 31, 2018)

2,523

2,388

Financing leases and other, maturing through 2071, weighted average interest rate of 4.7%

710

467

Debt issuance costs, discounts and other

(85)

(52)

13,498

10,026

Current portion of long-term debt

218

432

$

13,280

$

9,594