SCHEDULE I - PARENT COMPANY FINANCIAL INFORMATION (Condensed Statements of Cash Flows) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	$ 921	$ 2,966	$ 3,981
Cash flows from investing activities:
Acquisitions, net of cash acquired	(81)	(89)	(233)
Purchases of property and equipment, net	(546)	(575)	(1,004)
Purchases of investment securities	(6,440)	(8,185)	(7,552)
Proceeds from sale of investment securities	6,510	3,376	3,795
Maturities of investment securities	2,912	2,982	1,292
Changes in securities lending collateral receivable	(220)	(418)	0
Other	0	(50)	0
Net cash provided by (used in) investing activities	2,273	(2,952)	(3,492)
Cash flows from financing activities:
Proceeds from issuance of senior notes, net	1,481	2,232	2,544
Repayments of senior notes	(948)	(1,107)	(1,832)
(Repayments) proceeds from issuance of commercial paper, net	(5)	(907)	211
Change in book overdraft	(97)	50	55
Common stock repurchases	(151)	(817)	(1,573)
Dividends paid	(430)	(431)	(431)
Net cash used in financing activities	(1,215)	(2,487)	(856)
Increase (decrease) in cash and cash equivalents	1,979	(2,473)	(367)
Cash and cash equivalents at beginning of period	2,221	4,694	5,061
Cash and cash equivalents at end of period	4,200	2,221	4,694
Proceeds from sale of business, net	115	0	0
Changes in securities lending payable	220	418	0
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	2,495	3,454	3,042
Cash flows from investing activities:
Acquisitions, net of cash acquired	(81)	(89)	(233)
Capital contributions to operating subsidiaries	(1,024)	(1,698)	(792)
Purchases of property and equipment, net	(440)	(426)	(761)
Purchases of investment securities	(3)	(16)	(17)
Proceeds from sale of investment securities	8	0	41
Maturities of investment securities	27	32	67
Changes in securities lending collateral receivable	(2)	0	0
Other	0	(50)	0
Net cash provided by (used in) investing activities	(1,400)	(2,247)	(1,695)
Cash flows from financing activities:
Proceeds from issuance of senior notes, net	1,476	2,225	2,537
Repayments of senior notes	(948)	(1,107)	(1,832)
(Repayments) proceeds from issuance of commercial paper, net	(5)	(907)	211
Repayment of term loan	0	0	(500)
Change in book overdraft	(27)	(5)	2
Common stock repurchases	(151)	(817)	(1,573)
Dividends paid	(430)	(431)	(431)
Proceeds from stock option exercises and other	(13)	(86)	(125)
Net cash used in financing activities	(96)	(1,128)	(1,711)
Increase (decrease) in cash and cash equivalents	999	79	(364)
Cash and cash equivalents at beginning of period	329	250	614
Cash and cash equivalents at end of period	1,328	329	250
Proceeds from sale of business, net	115	0	0
Changes in securities lending payable	$ 2	$ 0	$ 0