SHARE CAPITAL - Preferred Shares (Details) $ / shares in Units, $ in Millions											1 Months Ended	12 Months Ended
	Dec. 01, 2023 $ / shares	Nov. 30, 2023 $ / shares	Sep. 01, 2023 $ / shares shares	Aug. 31, 2023 $ / shares	Jun. 01, 2023 $ / shares shares	Jun. 01, 2023 $ / shares shares	May 31, 2023 $ / shares	May 31, 2023 $ / shares	Mar. 01, 2023 $ / shares	Feb. 28, 2023 $ / shares	Jun. 30, 2023 shares	Dec. 31, 2023 CAD ($) $ / shares shares	Dec. 31, 2023 CAD ($) $ / shares $ / shares shares	Dec. 31, 2022 CAD ($) shares	Dec. 31, 2021 CAD ($) shares	Dec. 31, 2023 $ / shares	Jun. 01, 2022 CAD ($)	Mar. 01, 2022 CAD ($)
Preferred Shares
Share Capital
Preferred stock, value, outstanding | $												$ 6,818	$ 6,818	$ 6,818	$ 7,747
Issuance costs | $												$ (135)		$ (135)	$ (155)
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Preference shares conversion ratio												1	1
Preference Shares, Series A | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												5,000,000	5,000,000	5,000,000	5,000,000
Preferred stock, value, outstanding | $												$ 125	$ 125	$ 125	$ 125
Dividend rate (percent)												5.50%
Dividend (in Canadian dollars per share)												$ 1.37500
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Dividend rate reset period												5 years
Preference Shares, Series B | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												20,000,000	20,000,000	20,000,000	18,000,000
Preferred stock, value, outstanding | $												$ 500	$ 500	$ 500	$ 457
Dividend rate (percent)												5.20%
Dividend (in Canadian dollars per share)												$ 1.30052
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Preference Shares, Series C | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												0	0	0	2,000,000
Preferred stock, value, outstanding | $												$ 0	$ 0	$ 0	$ 43
Preference Shares, Series C | Preferred Shares | 3-Month Government Of Canada Treasury Bill
Share Capital
Dividend rate -spread on variable rate (percent)												2.40%	2.40%
Preference Shares, Series D | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												18,000,000	18,000,000	18,000,000	18,000,000
Preferred stock, value, outstanding | $												$ 450	$ 450	$ 450	$ 450
Dividend rate (percent)												5.41%
Dividend (in Canadian dollars per share)									$ 0.33825	$ 0.27875		$ 1.35300
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Preference Shares, Series F | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												18,000,000	18,000,000	20,000,000	20,000,000
Preferred stock, value, outstanding | $												$ 454	$ 454	$ 500	$ 500
Dividend rate (percent)												5.54%
Dividend (in Canadian dollars per share)					$ 0.34613		$ 0.29306					$ 1.38452
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Conversion of stock, shares converted | shares					1,827,695	1,827,695
Preference Shares, Series G | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												2,000,000	2,000,000	0	0
Preferred stock, value, outstanding | $												$ 46	$ 46	$ 0	$ 0
Dividend rate (percent)												6.96%
Dividend (in Canadian dollars per share)	$ 0.47676	$ 0.47245										$ 1.90704
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Conversion of stock, shares converted | shares											1,827,695
Preference Shares, Series G | Preferred Shares | 3-Month Government Of Canada Treasury Bill
Share Capital
Dividend rate -spread on variable rate (percent)												2.50%	2.50%
Preference Shares, Series H | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												12,000,000	12,000,000	14,000,000	14,000,000
Preferred stock, value, outstanding | $												$ 291	$ 291	$ 350	$ 350
Dividend rate (percent)												6.11%
Dividend (in Canadian dollars per share)			$ 0.38200	$ 0.27350								$ 1.52800
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Conversion of stock, shares converted | shares			2,350,602
Preference Shares, Series I | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												2,000,000	2,000,000	0	0
Preferred stock, value, outstanding | $												$ 59	$ 59	$ 0	$ 0
Dividend rate (percent)												7.19%
Dividend (in Canadian dollars per share)	0.45251	0.44814										$ 1.81004
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Preference Shares, Series I | Preferred Shares | 3-Month Government Of Canada Treasury Bill
Share Capital
Dividend rate -spread on variable rate (percent)												2.10%	2.10%
Preference Shares, Series J
Share Capital
Preferred stock, redemption amount | $																	$ 200
Preference Shares, Series J | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												0	0	0	8,000,000
Preferred stock, value, outstanding | $												$ 0	$ 0	$ 0	$ 199
Preference Shares, Series L | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												16,000,000	16,000,000	16,000,000	16,000,000
Preferred stock, value, outstanding | $												$ 411	$ 411	$ 411	$ 411
Dividend rate (percent)												5.86%
Dividend (in Canadian dollars per share)													$ 1.46448
Per share base redemption value (in Canadian dollars per shares)																$ 25
Preference Shares, Series N | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												18,000,000	18,000,000	18,000,000	18,000,000
Preferred stock, value, outstanding | $												$ 450	$ 450	$ 450	$ 450
Dividend rate (percent)												6.70%
Dividend (in Canadian dollars per share)	$ 0.41850	$ 0.31788										$ 1.67400
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Preference Shares, Series P | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												16,000,000	16,000,000	16,000,000	16,000,000
Preferred stock, value, outstanding | $												$ 400	$ 400	$ 400	$ 400
Dividend rate (percent)												4.38%
Dividend (in Canadian dollars per share)												$ 1.09476
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Preference Shares, Series R | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												16,000,000	16,000,000	16,000,000	16,000,000
Preferred stock, value, outstanding | $												$ 400	$ 400	$ 400	$ 400
Dividend rate (percent)												4.07%
Dividend (in Canadian dollars per share)												$ 1.01825
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Preference Shares, Series 1 | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												16,000,000	16,000,000	16,000,000	16,000,000
Preferred stock, value, outstanding | $												$ 411	$ 411	$ 411	$ 411
Dividend rate (percent)												6.70%
Dividend (in Canadian dollars per share)						$ 0.41898		$ 0.37182					$ 1.67592
Per share base redemption value (in Canadian dollars per shares)																25
Preference Shares, Series 3 | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												24,000,000	24,000,000	24,000,000	24,000,000
Preferred stock, value, outstanding | $												$ 600	$ 600	$ 600	$ 600
Dividend rate (percent)												3.74%
Dividend (in Canadian dollars per share)												$ 0.93425
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Preference Shares, Series 5 | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												8,000,000	8,000,000	8,000,000	8,000,000
Preferred stock, value, outstanding | $												$ 206	$ 206	$ 206	$ 206
Dividend rate (percent)												5.38%
Dividend (in Canadian dollars per share)													$ 1.34383
Per share base redemption value (in Canadian dollars per shares)																$ 25
Preference Shares, Series 7 | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												10,000,000	10,000,000	10,000,000	10,000,000
Preferred stock, value, outstanding | $												$ 250	$ 250	$ 250	$ 250
Dividend rate (percent)												4.45%
Dividend (in Canadian dollars per share)												$ 1.11224
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Preference Shares, Series 9 | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												11,000,000	11,000,000	11,000,000	11,000,000
Preferred stock, value, outstanding | $												$ 275	$ 275	$ 275	$ 275
Dividend rate (percent)												4.10%
Dividend (in Canadian dollars per share)												$ 1.02424
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Preference Shares, Series 11 | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												20,000,000	20,000,000	20,000,000	20,000,000
Preferred stock, value, outstanding | $												$ 500	$ 500	$ 500	$ 500
Dividend rate (percent)												3.94%
Dividend (in Canadian dollars per share)												$ 0.98452
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Preference Shares, Series 13 | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												14,000,000	14,000,000	14,000,000	14,000,000
Preferred stock, value, outstanding | $												$ 350	$ 350	$ 350	$ 350
Dividend rate (percent)												3.04%
Dividend (in Canadian dollars per share)												$ 0.76076
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Preference Shares, Series 15 | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												11,000,000	11,000,000	11,000,000	11,000,000
Preferred stock, value, outstanding | $												$ 275	$ 275	$ 275	$ 275
Dividend rate (percent)												2.98%
Dividend (in Canadian dollars per share)												$ 0.74576
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Preference Shares, Series 17
Share Capital
Preferred stock, redemption amount | $																		$ 750
Preference Shares, Series 17 | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												0	0	0	30,000,000
Preferred stock, value, outstanding | $												$ 0	$ 0	$ 0	$ 750
Preference Shares, Series 19 | Preferred Shares
Share Capital
Preferred stock, shares outstanding (in shares) | shares												20,000,000	20,000,000	20,000,000	20,000,000
Preferred stock, value, outstanding | $												$ 500	$ 500	$ 500	$ 500
Dividend rate (percent)												6.21%
Dividend (in Canadian dollars per share)									$ 0.38825	$ 0.30625		$ 1.55300
Per share base redemption value (in Canadian dollars per shares)												$ 25	$ 25
Dividend rate reset period												5 years
Preference Shares, Series 19 | Minimum | Preferred Shares
Share Capital
Dividend rate (percent)												4.90%
Preference Shares, Series E | Preferred Shares | 3-Month Government Of Canada Treasury Bill
Share Capital
Dividend rate -spread on variable rate (percent)												2.40%	2.40%
Preference Shares, Series O | Preferred Shares | 3-Month Government Of Canada Treasury Bill
Share Capital
Dividend rate -spread on variable rate (percent)												2.70%	2.70%
Preference Shares, Series Q | Preferred Shares | 3-Month Government Of Canada Treasury Bill
Share Capital
Dividend rate -spread on variable rate (percent)												2.50%	2.50%
Preference Shares, Series S | Preferred Shares | 3-Month Government Of Canada Treasury Bill
Share Capital
Dividend rate -spread on variable rate (percent)												2.50%	2.50%
Preference Shares, Series 4 | Preferred Shares | 3-Month Government Of Canada Treasury Bill
Share Capital
Dividend rate -spread on variable rate (percent)												2.40%	2.40%
Preference Shares, Series 8 | Preferred Shares | 3-Month Government Of Canada Treasury Bill
Share Capital
Dividend rate -spread on variable rate (percent)												2.60%	2.60%
Preference Shares, Series 10 | Preferred Shares | 3-Month Government Of Canada Treasury Bill
Share Capital
Dividend rate -spread on variable rate (percent)												2.70%	2.70%
Preference Shares, Series 12 | Preferred Shares | 3-Month Government Of Canada Treasury Bill
Share Capital
Dividend rate -spread on variable rate (percent)												2.60%	2.60%
Preference Shares, Series M | 3-Month Government Of Canada Treasury Bill
Share Capital
Dividend rate -spread on variable rate (percent)												3.20%	3.20%
Preference Shares, Series 2 | 3-Month Government Of Canada Treasury Bill
Share Capital
Dividend rate -spread on variable rate (percent)												3.10%	3.10%
Preference Shares, Series 6 | 3-Month Government Of Canada Treasury Bill
Share Capital
Dividend rate -spread on variable rate (percent)												2.80%	2.80%