Long-Term Debt (Schedule of Long-Term Debt) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Long-term debt	$ 21,493	$ 19,114
Senior Notes 3.38% Due 2013 [Member]
Debt Instrument [Line Items]
Long-term debt	0	500
Interest rate	3.38%
Debt instrument, year of maturity	Dec. 31, 2013
Senior Notes 5.70% Due 2014 [Member]
Debt Instrument [Line Items]
Long-term debt	510	510
Interest rate	5.70%
Debt instrument, year of maturity	Dec. 31, 2014
Senior Notes 2.05% Due 2014 [Member]
Debt Instrument [Line Items]
Long-term debt	700	700
Interest rate	2.05%
Debt instrument, year of maturity	Dec. 31, 2014
Floating Rate Senior Notes Due 2014 [Member]
Debt Instrument [Line Items]
Long-term debt	300	300
Interest rate	0.94%
Debt instrument, year of maturity	Dec. 31, 2014
Senior Notes 3.95% Due 2016 [Member]
Debt Instrument [Line Items]
Long-term debt	500	500
Interest rate	3.95%
Debt instrument, year of maturity	Dec. 31, 2016
Senior Notes 3.20% Due 2016 [Member]
Debt Instrument [Line Items]
Long-term debt	999	999
Interest rate	3.20%
Debt instrument, year of maturity	Dec. 31, 2016
Senior Notes 2.15% Due 2017 [Member]
Debt Instrument [Line Items]
Long-term debt	749	748
Interest rate	2.15%
Debt instrument, year of maturity	Dec. 31, 2017
Senior Notes 1.60% Due 2017 [Member]
Debt Instrument [Line Items]
Long-term debt	749	749
Interest rate	1.60%
Debt instrument, year of maturity	Dec. 31, 2017
Senior Notes 1.45% Due 2018 [Member]
Debt Instrument [Line Items]
Long-term debt	500	499
Interest rate	1.45%
Debt instrument, year of maturity	Dec. 31, 2018
Floating Rate Senior Notes Due 2018 [Member]
Debt Instrument [Line Items]
Long-term debt	400	0
Interest rate	1.10%
Debt instrument, year of maturity	Dec. 31, 2018
Senior Notes 2.05% Due 2018 [Member]
Debt Instrument [Line Items]
Long-term debt	599	0
Interest rate	2.05%
Debt instrument, year of maturity	Dec. 31, 2018
Senior Notes 6.85% Due 2019 [Member]
Debt Instrument [Line Items]
Long-term debt	539	539
Interest rate	6.85%
Debt instrument, year of maturity	Dec. 31, 2019
Subordinated Notes 5.20% Due 2015 [Member]
Debt Instrument [Line Items]
Long-term debt	933	933
Interest rate	5.20%
Debt instrument, year of maturity	Dec. 31, 2015
Subordinated Notes 4.90% Due 2017 [Member]
Debt Instrument [Line Items]
Long-term debt	349	345
Interest rate	4.90%
Debt instrument, year of maturity	Dec. 31, 2017
Subordinated Notes 5.25% Due 2019 [Member]
Debt Instrument [Line Items]
Long-term debt	586	586
Interest rate	5.25%
Debt instrument, year of maturity	Dec. 31, 2019
Subordinated Notes 3.95% Due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	298	298
Interest rate	3.95%
Debt instrument, year of maturity	Dec. 31, 2022
Floating Rate Senior Note Due 2015 [Member] | Branch Bank [Member]
Debt Instrument [Line Items]
Long-term debt	650	0
Effective interest rate at the end of the period	0.57%
Debt instrument, year of maturity	Dec. 31, 2015
Senior Notes 1.45% Due 2016 [Member] | Branch Bank [Member]
Debt Instrument [Line Items]
Long-term debt	750	0
Interest rate	1.45%
Debt instrument, year of maturity	Dec. 31, 2016
Floating Rate Senior Notes Due 2016 [Member] | Branch Bank [Member]
Debt Instrument [Line Items]
Long-term debt	500	0
Interest rate	0.67%
Debt instrument, year of maturity	Dec. 31, 2016
Senior Notes 1.05% Due 2016 [Member] | Branch Bank [Member]
Debt Instrument [Line Items]
Long-term debt	499	0
Interest rate	1.05%
Debt instrument, year of maturity	Dec. 31, 2016
Senior Notes 2.30% Due 2018 [Member] | Branch Bank [Member]
Debt Instrument [Line Items]
Long-term debt	750	0
Interest rate	2.30%
Debt instrument, year of maturity	Dec. 31, 2018
Subordinated Notes 4.88% Due 2013 [Member] | Branch Bank [Member]
Debt Instrument [Line Items]
Long-term debt	0	222
Interest rate	4.88%
Debt instrument, year of maturity	Dec. 31, 2013
Subordinated Notes 5.63% Due 2016 [Member] | Branch Bank [Member]
Debt Instrument [Line Items]
Long-term debt	386	386
Interest rate	5.63%
Debt instrument, year of maturity	Dec. 31, 2016
Floating Rate Subordinated Notes Due 2016 [Member] | Branch Bank [Member]
Debt Instrument [Line Items]
Long-term debt	350	350
Interest rate	0.56%
Debt instrument, year of maturity	Dec. 31, 2016
Floating Rate Subordinated Notes Due 2017 [Member] | Branch Bank [Member]
Debt Instrument [Line Items]
Long-term debt	262	262
Interest rate	0.54%
Debt instrument, year of maturity	Dec. 31, 2017
Varying maturities to 2034 [Member] | Federal Home Loan Bank Advances to Branch Bank [Member]
Debt Instrument [Line Items]
Long-term debt	8,110	8,994
Debt instrument, year of maturity	Dec. 31, 2034
Other Long-Term Debt [Member]
Debt Instrument [Line Items]
Long-term debt	101	100
Fair Value Hedge-Related Basis Adjustments [Member]
Debt Instrument [Line Items]
Long-term debt	$ 424	$ 594