Debt - Components (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2019
Short-term debt:
Total short-term debt	$ 831	$ 822
Long-term debt:
PAA senior notes, net of unamortized discounts and debt issuance costs	9,071	8,329
Noncurrent portion of other long-term debt	311	69
Total long-term debt	9,382	8,398
Total debt	10,213	9,220
PAA senior notes
Long-term debt:
Unamortized discounts and debt issuance costs	(62)	(54)
PAA senior notes, net of unamortized discounts and debt issuance costs	9,071	8,329
Senior notes repurchase amount	17
Debt instrument face value	9,100	9,100
PAA senior notes | Other income/(expense), net
Long-term debt:
Gain on repurchase of senior notes	3
PAA senior notes | Level 2
Long-term debt:
Debt instrument fair value	9,900	$ 9,900
PAA senior notes | 3.65% senior notes due June 2022
Short-term debt:
Debt instrument, interest rate (as a percent)		3.65%
Long-term debt:
Long-term debt, before deducting unamortized discounts and debt issuance costs	750	$ 0
PAA senior notes | 2.85% senior notes due January 2023
Short-term debt:
Debt instrument, interest rate (as a percent)		2.85%
Long-term debt:
Long-term debt, before deducting unamortized discounts and debt issuance costs	400	$ 400
PAA senior notes | 3.85% senior notes due October 2023
Short-term debt:
Debt instrument, interest rate (as a percent)		3.85%
Long-term debt:
Long-term debt, before deducting unamortized discounts and debt issuance costs	700	$ 700
PAA senior notes | 3.60% senior notes due November 2024
Short-term debt:
Debt instrument, interest rate (as a percent)		3.60%
Long-term debt:
Long-term debt, before deducting unamortized discounts and debt issuance costs	750	$ 750
PAA senior notes | 4.65% senior notes due October 2025
Short-term debt:
Debt instrument, interest rate (as a percent)		4.65%
Long-term debt:
Long-term debt, before deducting unamortized discounts and debt issuance costs	1,000	$ 1,000
PAA senior notes | 4.50% senior notes due December 2026
Short-term debt:
Debt instrument, interest rate (as a percent)		4.50%
Long-term debt:
Long-term debt, before deducting unamortized discounts and debt issuance costs	750	$ 750
PAA senior notes | 3.55% senior notes due December 2029
Short-term debt:
Debt instrument, interest rate (as a percent)		3.55%	3.55%
Long-term debt:
Long-term debt, before deducting unamortized discounts and debt issuance costs	$ 1,000	$ 1,000
Debt instrument face value			$ 1,000
PAA senior notes | 3.80% senior notes due September 2030
Short-term debt:
Debt instrument, interest rate (as a percent)	3.80%	3.80%
Long-term debt:
Long-term debt, before deducting unamortized discounts and debt issuance costs	$ 750	$ 750
Debt instrument face value	750
PAA senior notes | 6.70% senior notes due May 2036
Short-term debt:
Debt instrument, interest rate (as a percent)		6.70%
Long-term debt:
Long-term debt, before deducting unamortized discounts and debt issuance costs	250	$ 250
PAA senior notes | 6.65% senior notes due January 2037
Short-term debt:
Debt instrument, interest rate (as a percent)		6.65%
Long-term debt:
Long-term debt, before deducting unamortized discounts and debt issuance costs	600	$ 600
PAA senior notes | 5.15% senior notes due June 2042
Short-term debt:
Debt instrument, interest rate (as a percent)		5.15%
Long-term debt:
Long-term debt, before deducting unamortized discounts and debt issuance costs	499	$ 499
PAA senior notes | 4.30% senior notes due January 2043
Short-term debt:
Debt instrument, interest rate (as a percent)		4.30%
Long-term debt:
Long-term debt, before deducting unamortized discounts and debt issuance costs	348	$ 348
PAA senior notes | 4.70% senior notes due June 2044
Short-term debt:
Debt instrument, interest rate (as a percent)		4.70%
Long-term debt:
Long-term debt, before deducting unamortized discounts and debt issuance costs	687	$ 687
PAA senior notes | 4.90% senior notes due February 2045
Short-term debt:
Debt instrument, interest rate (as a percent)		4.90%
Long-term debt:
Long-term debt, before deducting unamortized discounts and debt issuance costs	649	$ 649
Term loan | GO Zone Term Loans
Long-term debt:
Noncurrent portion of other long-term debt	199
Debt issuance costs	$ 1
Weighted average long term debt interest rate	1.30%
Other long-term debt
Long-term debt:
Noncurrent portion of other long-term debt	$ 112	69
Line of Credit | PAA commercial paper notes
Short-term debt:
Short-term notes and borrowings	$ 547	0
Weighted average interest rate, short-term	0.70%
Line of Credit | PAA senior secured hedged inventory facility
Short-term debt:
Short-term notes and borrowings	$ 167	0
Weighted average interest rate, short-term	1.20%
PAA senior notes | 3.65% senior notes due June 2022
Short-term debt:
Short-term notes and borrowings	$ 0	$ 750
Debt instrument, interest rate (as a percent)		3.65%
Other
Short-term debt:
Total short-term debt	$ 117	$ 72