Fair Value (Tables)

6 Months Ended

Jun. 30, 2019

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial Assets and Liabilities, Measured at Fair Value Recurring Basis [Table Text Block]

The following table presents a summary of fair value measurements by level and carrying values for items measured at fair value on a recurring basis in the Condensed Consolidated Balance Sheets:

(in millions)	Quoted Prices in Active Markets (Level 1)			Other Observable Inputs (Level 2)			Unobservable Inputs (Level 3)			Total Fair and Carrying Value
June 30, 2019
Cash and cash equivalents	$	13,562		$	183		$	—		$	13,745
Debt securities - available-for-sale:
U.S. government and agency obligations	3,474			285			—			3,759
State and municipal obligations	—			6,768			—			6,768
Corporate obligations	65			16,583			202			16,850
U.S. agency mortgage-backed securities	—			5,730			—			5,730
Non-U.S. agency mortgage-backed securities	—			1,631			—			1,631
Total debt securities - available-for-sale	3,539			30,997			202			34,738
Equity securities	2,035			15			—			2,050
Assets under management	1,011			1,911			21			2,943
Total assets at fair value	$	20,147		$	33,106		$	223		$	53,476
Percentage of total assets at fair value	38		%	62		%	—		%	100		%
December 31, 2018
Cash and cash equivalents	$	10,757		$	109		$	—		$	10,866
Debt securities - available-for-sale:
U.S. government and agency obligations	3,060			345			—			3,405
State and municipal obligations	—			7,121			—			7,121
Corporate obligations	39			14,950			173			15,162
U.S. agency mortgage-backed securities	—			4,852			—			4,852
Non-U.S. agency mortgage-backed securities	—			1,358			—			1,358
Total debt securities - available-for-sale	3,099			28,626			173			31,898
Equity securities	1,832			13			—			1,845
Assets under management	1,086			1,938			8			3,032
Total assets at fair value	$	16,774		$	30,686		$	181		$	47,641
Percentage of total assets at fair value	35		%	65		%	—		%	100		%

Fair Value Measurements, Nonrecurring [Table Text Block]

The following table presents a summary of fair value measurements by level and carrying values for certain financial instruments not measured at fair value on a recurring basis in the Condensed Consolidated Balance Sheets:

(in millions)	Quoted Prices in Active Markets (Level 1)		Other Observable Inputs (Level 2)		Unobservable Inputs (Level 3)		Total Fair Value		Total Carrying Value
June 30, 2019
Debt securities - held-to-maturity	$	293	$	177	$	275	$	745	$	741
Long-term debt and other financing obligations	$	—	$	38,927	$	—	$	38,927	$	35,300
December 31, 2018
Debt securities - held-to-maturity	$	260	$	65	$	295	$	620	$	621
Long-term debt and other financing obligations	$	—	$	37,944	$	—	$	37,944	$	36,554