Long-Term Debt and Shareholders' Equity (Changes In Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ 5,829	$ 5,184	$ 5,691	$ 4,893
Other comprehensive income (loss) before reclassifications, net of tax			(2)	12
Amounts reclassified from AOCI, net of tax			145	170
Other comprehensive income (loss), net of tax	60	(10)	143	182
Balance at end of period	6,025	5,283	6,025	5,283
Income tax expense included in OCI			47	59
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(2,609)	(2,920)	(2,692)	(3,112)
Balance at end of period	(2,549)	(2,930)	(2,549)	(2,930)
Net unrealized gains/(losses) on investment securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period			(2,526)	(2,800)
Other comprehensive income (loss) before reclassifications, net of tax			(2)	(9)
Amounts reclassified from AOCI, net of tax			96	103
Other comprehensive income (loss), net of tax			94	94
Balance at end of period	(2,432)	(2,706)	(2,432)	(2,706)
Income tax expense included in OCI			31	31
Net unrealized gains/(losses) on derivatives and other
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period			(165)	(311)
Other comprehensive income (loss) before reclassifications, net of tax			0	21
Amounts reclassified from AOCI, net of tax			49	67
Other comprehensive income (loss), net of tax			49	88
Balance at end of period	(116)	(223)	(116)	(223)
Income tax expense included in OCI			16	28
Pension and post-retirement
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period			(1)	(1)
Other comprehensive income (loss) before reclassifications, net of tax			0	0
Amounts reclassified from AOCI, net of tax			0	0
Other comprehensive income (loss), net of tax			0	0
Balance at end of period	$ (1)	$ (1)	(1)	(1)
Income tax expense included in OCI			$ 0	$ 0