Condensed Statement of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities
Net cash provided by (used in) operating activities	$ 3,263	$ 3,122	$ 3,126
Investing activities
Net cash provided by (used in) investing activities	(4,343)	(3,986)	(3,296)
Financing activities
Proceeds from (repayment of) short-term borrowings, net	(443)	225	422
Proceeds from issuance of long-term debt	2,920	1,675	1,518
Repayment of long-term debt	(949)	(452)	(1,030)
Proceeds from Issuance of Common Stock	458	230	0
Dividends paid	(791)	(730)	(721)
Other, net	(14)	(20)	(21)
Net cash provided by (used in) financing activities	1,181	928	168
Net change in cash and cash equivalents	101	64	(2)
Cash and cash equivalents at beginning of period	147	83	85
Cash and cash equivalents at end of period	248	147	83
Xcel Energy Inc.
Operating activities
Net cash provided by (used in) operating activities	1,389	1,210	1,208
Investing activities
Capital contributions to subsidiaries	(1,594)	(809)	(849)
Investments in the utility money pool	(1,054)	(2,578)	(1,258)
Return of investments in the utility money pool	1,093	2,493	1,173
Net cash provided by (used in) investing activities	(1,555)	(894)	(934)
Financing activities
Proceeds from (repayment of) short-term borrowings, net	12	(295)	715
Proceeds from issuance of long-term debt	1,120	492	0
Repayment of long-term debt	(550)	0	(250)
Proceeds from Issuance of Common Stock	458	230	0
Repurchases of common stock	0	(1)	(3)
Dividends paid	(791)	(730)	(721)
Other, net	(14)	(12)	(14)
Net cash provided by (used in) financing activities	235	(316)	(273)
Net change in cash and cash equivalents	69	0	1
Cash and cash equivalents at beginning of period	1	1	0
Cash and cash equivalents at end of period	$ 70	$ 1	$ 1